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1. The objective of this study was to determine if rearing broilers under variable light intensity (VLI) impacted their welfare or productivity.2. Ross 308 broilers (n = 7,256) were reared until 35 d of age and exposed to a uniform intensity of 10 lux (CON) or VLI with low intensity areas of 2–5 lux proximal to the walls and high intensity areas of 84–133 lux proximal to feeders.3. The data were analysed as a complete randomised design using an analysis of variance. Significance was declared when p ≤ 0.05.4. Applying VLI resulted in increased feed intake early in life but had no impact on body weight. Overall efficiency was improved in the CON treatment. Mortality diagnoses of skeletal problems were reduced under VLI. Treatment had no impact on footpad, hock or gait score, heterophil to lymphocyte ratio or melatonin concentration. Birds performed certain behaviours in specific locations within the room, independent of light intensity treatment.5. In conclusion, raising broilers under VLI had little impact on production or most welfare parameters assessed in this study. However, satisfying the bird’s preference for different light intensities may improve welfare. [ABSTRACT FROM AUTHOR]

ABSTRACT: Woody or wooden breast (WB) is characterized by hardening and paleness of the Pectoralis major muscle and can affect up to 85% of broilers. We hypothesized that increased locomotor activity would lead to a lower prevalence of WB and increased tibia bone quality, with a greater effect on a faster growing than a slower growing broiler strain. Ross 708 (N = 188) and Ranger Gold (N = 213) broilers were raised in 3.05×3.05 m2 pens in groups of 23 to 24 and 26 to 27, respectively. Target ages for the Ross 708 and Ranger Gold birds were 42 and 56 d. There were 8 pens per strain: 4 assigned to an exercise treatment and 4 unexercised controls. An exercise regimen was applied for 10 min every hour for 6 h during each weekday with the goal of increasing frequency of standing and walking. A perch was placed between the feeder and drinker line in the exercise treatment pens to further promote broiler activity. WB severity was determined by palpation for all birds at the target age. Tibial bone mineral content (BMC) and bone mineral density (BMD) were measured using a dual-energy x-ray absorptiometry. The Fisher's Exact Test was used to determine treatment effects on the prevalence and severity of WB. Both prevalence (Ross 708: 77.5 vs. 90.5% control, P = 0.013; Ranger Gold: 57.9 vs. 76.4% control, P = 0.005) and severity (Ross 708: 12.9 vs. 24.2% control, P = 0.02; Ranger Gold: 4.7 vs. 0.02% control, P = 0.01) were reduced by treatment. The effects of strain, treatment and their interaction on tibial BMC and BMD were analyzed using linear mixed models. Only strain affected BMC (P = 0.003) and BMD (P = 0.03), with Ross 708 broilers having higher BMC (control: 3.246 g ± 0.061; treatment: 3.251 g ± 0.058) and BMD (control: 0.177 g/cm2 ± 0.002; treatment: 0.174 g/cm2 ± 0.002) values compared to Ranger Gold's BMC (control: 2.966 g ± 0.067; treatment: 2.987 g ± 0.064) and BMD (control: 0.168 g/cm2 ± 0.002; treatment: 0.168 g/cm2 ± 0.002) values. However, per unit of final body weight, Ranger Gold birds had a significantly higher BMC (P = 0.006) and BMD (P = 0.01) than Ross 708 broilers. Promoting broiler activity can reduce the prevalence and severity of WB prevalence in fast and slow growing broilers.

Background: Active bone remodeling processes can be altered by the presence of reactive oxygen species and, therefore, cause leg problems in broiler chickens. The antioxidant activity present in grape seed extract (GSE) could be a viable alternative to high inclusion levels of vitamin E (VE) as a nutritional strategy to improve the antioxidant capacity of birds and, thus, prevent leg abnormalities. Objective: To evaluate the effect of partial substitution of VE with grape GSE on leg health and performance of broiler chickens. Methods: Four hundred and twenty newly-hatched Ross 308 male broiler chickens were distributed into three treatments: 1) Control-AL, a diet containing 40 IU/kg of VE and fed ad libitum (CAL); 2) Control-FR, the CAL diet but offered through a feed restriction program (CFR); and 3) grape seed extract-AL, a diet containing 10 mg/kg of GSE + 10 IU/kg of VE fed ad libitum (GSE-AL). The trial was conducted for 47 days. Feed intake and body weight of the chickens were recorded weekly to evaluate performance. At day 43, gait score (GS), valgus/varus angulation (AngV), foot burn (FB), and hock burn (HB) lesions were evaluated. At day 47, tibia-breaking strength (TBS) and gastrocnemius tendon-breaking strength (GTBS) were evaluated. Results: Birds in the GSE-AL treatment showed reduced (p=0.05) GS compared to the other treatments. No statistical differences (p>0.05) were found in AngV, HB, FB, TBS, TGBS, and growth performance among treatments. Conclusions: These results suggest that GSE may partially replace VE in broiler diets without negative effects on growth performance or leg health. Further research is required to evaluate the potential of grape seed extract to replace VE or other ingredients with antioxidant activity under different rearing conditions and feeding programs. [ABSTRACT FROM AUTHOR]

Due to concerns about the welfare of fast-growing (FG) strains of broiler chicken, animal welfare organisations have advocated the use of certain slower-growing (SG) strains that meet key welfare targets under test conditions. However, a widespread transition to SG strains could negatively affect sustainability because these birds tend to have higher feed conversion ratios and longer production cycles. It is important therefore to review the extent and limits of SG welfare improvements under test conditions and on commercial farms, to support the best policy decisions. Following a systematic literature search, 63 source papers were identified. Most reported comparative welfare outcomes for at least one SG strain with at least one FG counterpart, whilst a minority examined the suitability of various SG strains for niche production. The literature review considered different types of study design and accounted for confounding factors such rearing environment and diet. Additionally, a quantitative analysis of effect size for mortality, gait score and contact dermatitis was conducted across studies that had compared birds under similar rearing conditions and that had used SG strains with an average daily growth rate of at least 40g/day. Modern, commercial SG strains performed better on most relevant welfare traits than FG strains. This was the case even when the 'fairest' comparisons were made at equivalent bodyweights (when SG birds were older), under matched-environmental conditions, experimentally or on farm. The quantitative analysis found that FG strains had a higher estimated incidence rate ratio for mortality (risk of death over a given period of time) of between 1.69 and 2.16, contact dermatitis affecting 15-25% more birds, and a mean gait score 0.65 points higher than SG strains. FG strains were also less active but other differences in behaviour were inconsistent with some behaviours (e.g. dustbathing) often absent altogether. Growth rate was generally, but not always, predictive of welfare problems. Alternative strategies, such as the slaughter of birds prior to the onset of any welfare decline, could be evaluated in future in terms of welfare improvement and efficiency of production. [ABSTRACT FROM AUTHOR]

Due to concerns about the welfare of fast-growing (FG) strains of broiler chicken, animal welfare organisations have advocated the use of certain slower-growing (SG) strains that meet key welfare targets under test conditions. However, a widespread transition to SG strains could negatively affect sustainability because these birds tend to have higher feed conversion ratios and longer production cycles. It is important therefore to review the extent and limits of SG welfare improvements under test conditions and on commercial farms, to support the best policy decisions. Following a systematic literature search, 63 source papers were identified. Most reported comparative welfare outcomes for at least one SG strain with at least one FG counterpart, whilst a minority examined the suitability of various SG strains for niche production. The literature review considered different types of study design and accounted for confounding factors such rearing environment and diet. Additionally, a quantitative analysis of effect size for mortality, gait score and contact dermatitis was conducted across studies that had compared birds under similar rearing conditions and that had used SG strains with an average daily growth rate of at least 40g/day. Modern, commercial SG strains performed better on most relevant welfare traits than FG strains. This was the case even when the ‘fairest’ comparisons were made at equivalent bodyweights (when SG birds were older), under matched-environmental conditions, experimentally or on farm. The quantitative analysis found that FG strains had a higher estimated incidence rate ratio for mortality (risk of death over a given period of time) of between 1.69 and 2.16, contact dermatitis affecting 15-25% more birds, and a mean gait score 0.65 points higher than SG strains. FG strains were also less active but other differences in behaviour were inconsistent with some behaviours (e.g. dustbathing) often absent altogether. Growth rate was generally, but not always, predictive of welfare problems. Alternative strategies, such as the slaughter of birds prior to the onset of any welfare decline, could be evaluated in future in terms of welfare improvement and efficiency of production.

The production of soybean meal (SBM) has a substantial impact on the environment and reducing its inclusion in poultry diets by using alternative protein sources, such as insect meal, is an important challenge for nutritionists. This study aimed to compare the productive performance of broiler chickens fed one of two isonitrogenic (195 g/kg CP) and isocaloric (12.91 MJ/kg) diets. The first diet contained SBM as the main protein source, whereas SBM was completely replaced by defatted meal from Black Soldier Fly larvae (Hermetia illucens L.; BSFL) in the second diet. Compared to the BSFL diet, the final body weight (BW) and weight gain (WG) of birds fed the SBM diet was ~17% greater and feed was utilised 19% more efficiently (p < 0.05). The differences in WG and FCR were supported by improved energy metabolism metrics, fat digestibility and digestibility of acid detergent fibres (ADFD) (p < 0.05). The present study shows that a complete replacement of dietary SBM with BSFL meal must be achieved with care, ensuring that all other factors (e.g., insect processing technology, feed additive supplementation, non-protein nitrogen accounting, mineral balance, fatty acid profile, amino acid supplementation) have been considered.

The purpose of the research was to determine how stocking density affected the behaviour, growth, physiological responses, and leg condition of broilers. 195 five-day old, unsexed Ross strain chicks were randomly allotted into 3 treatments. low stocking density (10 birds/m2, LSD), medium stocking density (15 birds/m2, MSD) and high stocking density (18 birds/m2, HSD). Each treatment had 3 pens (1.5 m2), and approximately four weeks were spent on the study. The HSD demonstrated reduced rates (P < 0.05) of laying, locomotion, eating, preening and longer periods of tonic immobility. Final body weight and total body weight gain were significantly (P < 0.05) reduced in the HSD. Also, HSD group showed increased (P < 0.05) heterophil/lymphocyte ratio, serum corticosterone, glucose and cholesterol, and significantly increased gait issues and footpad and hock burns. However, no significant (P > 0.05) difference was found in litter quality (moisture, ASH, pH) and bone quality (tibiae and femurs measurements) between all treatments. Conclusion, the results indicate that HSD had a negative effect on broiler's behaviour and welfare indicators, therefore it should be avoided in poultry farms and further investigations are still required to figure out the best methods for its control. [ABSTRACT FROM AUTHOR]

The production of soybean meal (SBM) has a substantial impact on the environment and reducing its inclusion in poultry diets by using alternative protein sources, such as insect meal, is an important challenge for nutritionists. This study aimed to compare the productive performance of broiler chickens fed one of two isonitrogenic (195 g/kg CP) and isocaloric (12.91 MJ/kg) diets. The first diet contained SBM as the main protein source, whereas SBM was completely replaced by defatted meal from Black Soldier Fly larvae (Hermetia illucens L.; BSFL) in the second diet. Compared to the BSFL diet, the final body weight (BW) and weight gain (WG) of birds fed the SBM diet was ~17% greater and feed was utilised 19% more efficiently (p < 0.05). The differences in WG and FCR were supported by improved energy metabolism metrics, fat digestibility and digestibility of acid detergent fibres (ADFD) (p < 0.05). The present study shows that a complete replacement of dietary SBM with BSFL meal must be achieved with care, ensuring that all other factors (e.g., insect processing technology, feed additive supplementation, non-protein nitrogen accounting, mineral balance, fatty acid profile, amino acid supplementation) have been considered. [ABSTRACT FROM AUTHOR]

Selecting on increased breast meat yield and body weight (BW) is thought to be associated with the increasing prevalence of leg disorders. A disorder of particular importance is tibial dyschondroplasia (TD), which is characterized as uncalcified cartilage in the proximal area of the tibiotarsal bone, leading to increased lameness, reduced feed and water intake, and subsequently poorer production efficiency and increased pre-slaughter mortality. Although it is hypothesized that TD is more prevalent in fast-growing poultry, this relationship can vary across studies making it challenging to distill the relationship between BW and TD, especially as studies of TD span several decades. Therefore, a systematic literature search and meta-analysis was conducted to identify factors influencing TD incidence. To date, the systematic literature search has resulted in 21 eligible papers, although data are still being extracted from the literature. Data extracted from each study included TD incidence (%), BW (kg), species (turkeys vs. broilers), sex (male vs. female), and age (weeks) of the animals. Preliminary univariable models have been developed based on the current database. Univariable generalized linear mixed models were developed in SAS (PROC GLIMMIX) including study as a random effect to evaluate the relationship between TD incidence and BW, species, sex, and age. Turkeys (27.3 ± 0.08%) had a greater TD incidence than broilers (19.3 ± 0.03%); however, this difference was not significant (P = 0.3481). There was a tendency for age to influence TD incidence (P = 0.0553) and a significant effect of BW (P < 0.0001). TD incidence also tended to differ between the sexes, with greater incidence in males (22.9 ± 0.07%) than females (11.3 ± 0.05%; P = 0.0657). After extracting all available data from the literature, further analysis will be conducted to consider multivariable models to predict TD. As such, caution should be used when generalizing these results due to the preliminary nature of the database. With the currently available data, the results of this study support the relationship between BW/size and TD. Furthermore, this study illustrates that TD is a prevalent challenge in both major poultry species. Reducing TD incidence could significantly improve animal welfare and mitigate economic losses associated with pre-slaughter mortality. [ABSTRACT FROM AUTHOR]

In this study, growth performance, nutrient intake, thigh meat quality, fatty acid composition of thigh meat, and biomechanical characteristics of tibia of broiler chickens in response to phased restriction of dietary digestible lysine (dLys) were evaluated. A total of 180 male broiler chickens distributed to 3 experimental groups were fed control diets, 85% dLys diet in grower phase (GRO 85% dLys), or 85% dLys diets in grower and finisher phases (GRO-FIN 85% dLys). Feeding 85% dLys suppressed the feed intake that suppressed the growth performance, slaughter weight, and thigh weight of broiler chickens compared to control group (P < 0.05). Average daily dLys, Ca, and P intakes were suppressed in groups fed 85% dLys diets in comparison with control group (P < 0.05) due to the suppression of feed intake. While most fatty acid concentrations in thigh meat were not different among the groups, eicosanoic acid (C20:0) in thigh meat was greater in GRO-FIN 85% dLys group than control group (P = 0.002). Antioxidant status of thigh meat of broiler chickens was not affected by the phased restriction of dietary dLys compared to control group. Bone breaking strength and ultimate strength were greater in control group than 85% dLys groups (P < 0.05). In conclusion, phased dilution of dietary dLys to 85% of the required allowance yields weaker legs and tibia bones by suppressing the Ca and P intakes as a function of reduced feed intake in broiler chickens. [ABSTRACT FROM AUTHOR]

This study investigated the effect of various pasture species on the welfare and behavior of slow-growing broiler chickens in the free-range production system. After 21 days completely indoors, the birds were permitted access to outdoor pens cultivated with one of the following pasture treatments: Medicago sativa (A), Trifolium repens (WC), Lolium perenne (PR), and a mixture (Mix, A + WC + PR). The range availability was restricted between 08:30 and 16:30 daily. It was found that pasture type had a significant effect on the fluctuating asymmetry of the face and radius length (P < 0.01). Duration of tonic immobility and blood parameters did not differ among the pasture species and between sexes at 11 weeks of broiler age (P > 0.05). Pasture treatment had no significant effect on broiler behaviors (P > 0.05). However, the age of broilers had a significant effect on pecking, dustbathing, and scratching (P < 0.01). Pecking behavior was affected by the time of the day; morning and afternoon (P < 0.01). Location had a significant effect on pecking and stretching behaviors (P < 0.01). In the study, dustbathing behavior was significantly affected by the interaction between location and age (P < 0.01), age and time of the day (P < 0.01), and location, age, and time of the day (P < 0.05). Scratching behavior was significantly affected by the interaction between location and time of the day (P < 0.05) and location, age and time of the day (P < 0.01). Stretching behavior was significantly affected by the interaction between location and age (P < 0.05) and location, age and time of the day (P < 0.05). It was concluded that access to the studied pasture species does not affect the evaluated welfare traits and observed behaviors. Therefore, it is suggested that other pasture species should be investigated to identify their effect on slow-growing strains in the free-range production system. [ABSTRACT FROM AUTHOR]

Simple Summary: Broiler chickens are specifically bred for meat, and conventional breeds have been genetically selected for faster growth rates. Rapid growth is associated with a greater risk of lameness in broiler chickens, which is a major welfare concern associated with an economic loss for producers. Although defined as an individual's physical and mental state, welfare is often monitored at the group level and is at risk of overlooking individual issues. Body-mounted accelerometers measure movement and could potentially monitor individual welfare, including lameness. However, body-mounted sensors may alter behavior and/or impact welfare. We investigated relationships between accelerometer-recorded activity (all movement), weight, and lameness in broiler breeds with different growth rates. Wearing the device did not negatively impact lameness, and, except for preening more, birds behaved similarly to those not wearing accelerometers after 24 h. We found that faster-growing, heavier birds were less active compared to slower-growing, lighter birds, demonstrating that accelerometers could detect known influences on activity useful for general monitoring, but that accelerometer-detected activity was not linearly associated with lameness. Further research on accelerometer detection of more specific behavioral changes likely to be associated with lameness, such as non-linear acceleration with gait score, offers the possibility of better continuous monitoring of individuals to assess lameness objectively. Accelerometers are increasingly being investigated to detect animal behavior as a method for monitoring individual welfare that overcomes manual challenges associated with time, resource, and discrete sampling. We investigated the effects of broiler chicken hybrid (hereafter breed) and weight on accelerometer activity (activityA; calculated as percentage of time spent active (%)) and its association with lameness as a major broiler welfare concern. Accelerometers were attached to birds of different breeds on between 2 and 4 occasions from 26 to 30 days old (conventional breed CNV) and 26 to 49 days old (two slower-growing breeds SGH; SGN). At 2.2 kg, lameness was scored using a 6-point gait scoring system (0: unaffected to 5: severely lame). Linear mixed effects models and breed-stratified generalized linear models together with a random-effect meta-analysis were used for data analyses. ActivityA was lower in faster-growing, heavier birds compared to slower-growing, lighter birds, showing overall consistency with previous behavioral research, but did not vary linearly with gait score. Accelerometers offer the potential for simple broad-scale continuous monitoring of broiler chicken activity behavior that requires limited data processing. Exploration of the ability of accelerometers to capture more subtle and specific changes in behavioral patterning, such as non-linear acceleration with gait score that could indicate early development of lameness, warrants further investigation. [ABSTRACT FROM AUTHOR]

ABSTRACT: Inactivity and leg disorders negatively impact broiler welfare. Enrichment designed to increase barn complexity may encourage physical exercise. The study aim was to implement a second-generation laser enrichment device, previously shown to increase broiler activity, for extended periods of time and to measure behavior and tibia quality. A total of 1,360 Ross 708 broilers in 40 pens of 34 were assigned to laser enrichment or control (no laser enrichment) for 49 d. Seventy focal birds were randomly selected on d 0 for individual behavior analysis. Laser-enriched birds were exposed to 6-min laser periods 4 times daily. A 3-min novel object test was performed on all pens and tonic immobility was induced on 1 bird/pen on wk 1 and 6. Focal bird time budget and walking distance and pen-wide laser-following behavior and movement were obtained during laser periods d 0 to 8 and 1 d/wk through wk 7. Right tibias were collected from focal birds on d 49 for dual energy x-ray absorptiometry and bone breaking analysis. Time spent active during laser periods was increased on d 3, 6, and 8 and wk 2 to 3 in laser-enriched vs. control focal birds (P = 0.04). Time at the feeder was increased in laser-enriched focal birds on d 0, 3 to 4, and 8 and wk 2 and 4 (P < 0.01). Distance walked during laser periods was increased in laser-enriched focal birds on d 1, 3 to 5, 8, and wk 2 compared to the control (P < 0.01). Pen-wide movement was increased on d 0, 2, 4 to 8, and wk 1 to 5 and 7 in laser-enriched vs. control birds (P < 0.01). More laser-enriched broilers were within 25 cm of the novel object at 1 min 30 s than the control (P = 0.03), and latency to approach the novel object was reduced in both treatments at wk 6 compared to wk 1 (P < 0.01). Tonic immobility duration was increased by 123 s on wk 6 compared to wk 1, regardless of treatment (P < 0.01). Daily laser enrichment for extended periods increased bird activity without inducing fearfulness or altering tibia measures.

SUMMARY: With the overselection of broiler body weight (BW) and breast muscle weight (BMW), the incidence of leg disease has been gradually increasing, which has seriously affected the welfare and industrial economic development of broilers. In this study, we used gait score and X-ray to evaluate the leg health of fast large white-feather broiler chickens at the age of 6 to 7 wk. The combined use of the 2 methods improved the detection rate and accuracy of diagnosing chicken leg disease. Moreover, more than 70% of chickens with abnormal gait scores also appeared abnormal on X-ray. At the same time, the 40-day BW, 42-day BMW, 28- to 40-day body weight gain (BWG) and tibial bone strength (BS) of the abnormal broilers were significantly lower than those of normal chickens. The 28- to 40-day feed conversion rate (FCR) significantly increased relative to normal chickens (P < 0.05). The comprehensive application of this method would be more suitable for evaluating of commercial broiler leg diseases, and providing a more complete set of in vitro evaluation criteria for broiler leg diseases.

Woody or wooden breast (WB) is characterized by hardening and paleness of the Pectoralis major muscle and can affect up to 85% of broilers. We hypothesized that increased locomotor activity would lead to a lower prevalence of WB and increased tibia bone quality, with a greater effect on a faster growing than a slower growing broiler strain. Ross 708 (N = 188) and Ranger Gold (N = 213) broilers were raised in 3.05×3.05 m 2 pens in groups of 23 to 24 and 26 to 27, respectively. Target ages for the Ross 708 and Ranger Gold birds were 42 and 56 d. There were 8 pens per strain: 4 assigned to an exercise treatment and 4 unexercised controls. An exercise regimen was applied for 10 min every hour for 6 h during each weekday with the goal of increasing frequency of standing and walking. A perch was placed between the feeder and drinker line in the exercise treatment pens to further promote broiler activity. WB severity was determined by palpation for all birds at the target age. Tibial bone mineral content (BMC) and bone mineral density (BMD) were measured using a dual-energy x-ray absorptiometry. The Fisher's Exact Test was used to determine treatment effects on the prevalence and severity of WB. Both prevalence (Ross 708: 77.5 vs. 90.5% control, P = 0.013; Ranger Gold: 57.9 vs. 76.4% control, P = 0.005) and severity (Ross 708: 12.9 vs. 24.2% control, P = 0.02; Ranger Gold: 4.7 vs. 0.02% control, P = 0.01) were reduced by treatment. The effects of strain, treatment and their interaction on tibial BMC and BMD were analyzed using linear mixed models. Only strain affected BMC (P = 0.003) and BMD (P = 0.03), with Ross 708 broilers having higher BMC (control: 3.246 g ± 0.061; treatment: 3.251 g ± 0.058) and BMD (control: 0.177 g/cm 2 ± 0.002; treatment: 0.174 g/cm 2 ± 0.002) values compared to Ranger Gold's BMC (control: 2.966 g ± 0.067; treatment: 2.987 g ± 0.064) and BMD (control: 0.168 g/cm 2 ± 0.002; treatment: 0.168 g/cm 2 ± 0.002) values. However, per unit of final body weight, Ranger Gold birds had a significantly higher BMC (P = 0.006) and BMD (P = 0.01) than Ross 708 broilers. Promoting broiler activity can reduce the prevalence and severity of WB prevalence in fast and slow growing broilers., Competing Interests: DISCLOSURES The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Cirenio Hisasaga reports financial support was provided by Jastro-Shields Award, UC Davis. Cirenio Hisasaga reports financial support was provided by Western Poultry Scholarship and Research Foundation. Maja Makagon reports equipment, drugs, or supplies was provided by Lubing. Maja Makagon & Cirenio Hisasaga reports equipment, drugs, or supplies was provided by Pitman Family Farms. Maja Makagon is currently an Associate Editor for the Animal Behavior & Wellbeing Section of Poultry Science. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

ABSTRACT: Improving leg health will support broiler health and welfare. Known factors to improve leg health are: replacing inorganic by organic macro minerals in the diet, providing environmental enrichments and using slower-growing broilers. However, it remains unknown how fast- and slower-growing broilers respond to a combination of providing organic macro minerals and an elevated platform as enrichment with regard to leg health. Therefore, the aim of this study was to identify whether a combined treatment of organic macro minerals and a platform affected leg health, tibia characteristics, behavior and performance of fast- and slower-growing broilers in a semicommercial setting. The experiment had a 2 × 2 factorial arrangement, with 12.800 fast-growing (Ross 308) and 12.800 slower-growing (Hubbard JA757) broilers that were randomly allocated to a control (i.e., inorganic macro minerals without enrichment) or adapted treatment (i.e., organic macro minerals and a platform). Broilers were housed in groups of 800 per pen (47.5 m2), with 8 replicates per treatment (total of 32 pens). Performance was measured weekly and over the total rearing period. Behavior was observed via scan sampling at a target weight of 0.6 and 1.9 kg for both breeds. Walking ability (gait score), footpad dermatitis, and hock burn were assessed in 10 broilers per pen just prior to slaughter weight. Leg disorders and tibia characteristics were assessed in the same broilers at slaughter weight (2.3 kg). Hardly any interaction effects between breed and treatment were found on leg health, tibia characteristics, behavior or performance, suggesting fast- and slower-growing broilers responded to the treatment similarly. The adapted treatment improved tibia characteristics, and increased locomotion and performance, but did not affect leg disorders, walking ability or contact dermatitis in both fast- and slower-growing broilers. The positive effects of the adapted treatment on tibia characteristics in both fast- and slower-growing broilers may improve leg health, although the current study did not confirm this for leg disorders, walking ability or contact dermatitis.

ABSTRACT: Valgus-varus deformity (VVD) is one of the leg disorders affecting health and welfare of broiler chickens. In research, several protocols are used to determine the prevalence and/or severity of VVD. This study aimed to investigate effects of five different protocols on the angulation of the tibiotarsal-tarsometatarsal joint. Angulation was determined (1) in living chickens with fixation at the femorotibiotarsal joint; (2) in dead chickens without fixation; (3) in dead chickens with fixation; (4) in dissected legs, including muscles, but without skin; (5) in dissected legs, without muscles, but with intact joints. Fixation of the leg at the femorotibiotarsal joint largely reduced the angulation of the tibiotarsal-tarsometatarsal joint. When fixation was used, no differences in angulation were found when broilers were live, dead or legs were dissected, but when no fixation was used, angulation was considerably higher, due to a large lateral deviation of the leg. It can be concluded that in intact chickens, fixation of the femorotibiotarsal joint is essential to determine VVD angulation in an appropriate way.

Accelerometers are increasingly being investigated to detect animal behavior as a method for monitoring individual welfare that overcomes manual challenges associated with time, resource, and discrete sampling. We investigated the effects of broiler chicken hybrid (hereafter breed) and weight on accelerometer activity (activityA; calculated as percentage of time spent active (%)) and its association with lameness as a major broiler welfare concern. Accelerometers were attached to birds of different breeds on between 2 and 4 occasions from 26 to 30 days old (conventional breed CNV) and 26 to 49 days old (two slower-growing breeds SGH; SGN). At 2.2 kg, lameness was scored using a 6-point gait scoring system (0: unaffected to 5: severely lame). Linear mixed effects models and breed-stratified generalized linear models together with a random-effect meta-analysis were used for data analyses. ActivityA was lower in faster-growing, heavier birds compared to slower-growing, lighter birds, showing overall consistency with previous behavioral research, but did not vary linearly with gait score. Accelerometers offer the potential for simple broad-scale continuous monitoring of broiler chicken activity behavior that requires limited data processing. Exploration of the ability of accelerometers to capture more subtle and specific changes in behavioral patterning, such as non-linear acceleration with gait score that could indicate early development of lameness, warrants further investigation.

ABSTRACT: In this study, the mobility, incidence, and severity of contact dermatitis and litter moisture content were assessed in 14 strains of broiler chickens differing in growth rate. The strains encompassed 2 conventional (CONV; ADG0-48 > 60 g/d) and 12 slower growing (SG) strains categorized as FAST (ADG0-62 = 53-55 g/d), MOD (ADG0-62 = 50-51 g/d), and SLOW (ADG0-62 < 50 g/d), with 4 strains in each category. A total of 7,216 mixed-sex birds were equally allocated into 164 pens (44 birds/pen; 30 kg/m2) in a randomized incomplete block design, with each strain represented in 8 to 12 pens over 2–3 trials. From each pen, 4 to 6 birds were tested in the latency-to-lie (LTL) and group obstacle tests 1 wk prior to the birds reaching 2 target weights (TWs) of approximately 2.1 kg (TW1: 34 d for CONV and 48 d for SG strains) and 3.2 kg (TW2: 48 d for CONV and 62 d for SG strains). The incidence of footpad dermatitis (FPD) and hock burns (HB) were evaluated a day prior to each TW. Litter moisture content was determined biweekly from d 14 to d 56. At TW1, CONV and SLOW had longer LTL than FAST birds. At TW2, CONV, MOD, and FAST birds had similar LTL. At both TWs, CONV birds were lighter than FAST birds in the group obstacle test, yet their number of obstacle crossings was similar. At TW1, CONV birds had greater incidence of FPD than FAST and MOD, while at TW2, CONV birds had greater incidence than the other categories. The incidence of HB in CONV and MOD was greater than SLOW birds at TW1, while at TW2, the incidence of HB was greater in CONV and FAST birds vs. MOD and SLOW birds. Litter moisture content was high in all categories from d 28 onward. Our results indicate that both BW and growth rate influence leg strength and walking ability, whereas the overall high litter moisture content and to a lesser extent growth rate influenced the incidence of contact dermatitis.

Contact dermatitis, both on the foot pads and hocks, is a well-known health issue in broilers. Less is known about contact dermatitis in broiler breeders, however, although they have many risk factors for developing leg health problems in common with broilers. This study aimed to describe the prevalence and severity of contact dermatitis during the production cycle in 5 lines of broiler breeders, investigate possible causes of contact dermatitis, and study its relationship with gait, egg production, and floor egg percentage. Five commercially available genetic lines of broiler breeders were housed in 21 pens of 550 females and 50 males from 20 to 60 wk of age. Every 10 wk litter quality, leg health measurements (foot pad dermatitis, hock burn, and gait) and body weight were assessed of 50 random hens per pen. Total number of eggs, number of eggs laid outside the nest (floor eggs), and mortality were recorded daily per pen. Prevalence of foot pad dermatitis, hock burn, and gait problems increased with age. Litter quality started to decrease at 50 wk of age. Prevalence of foot pad dermatitis was affected by litter quality, whereas genetic line had little effect. One genetic line was more prone to developing hock burns, though generally the prevalence of hock burn (13%) was much lower than that of foot pad dermatitis (74%). The percentage of broiler breeders with gait problems increased up to 24% with age, but this was not related to the prevalence of contact dermatitis. The lines differed in body weight from 32 wk of age onwards, and a higher body weight was related to lower egg production and higher cumulative mortality. The percentage of floor eggs was not related to leg health parameters or genetic line. Broiler breeders thus have similar leg health problems as broilers, but these problems are not related to the percentage of floor eggs, suggesting that other factors are involved in the undesirable behavior of floor laying.

This study was designed to determine effects of eggshell temperature (EST) pattern in week 2 and week 3 of incubation on tibia development of broiler chickens at slaughter age. A total of 468 Ross 308 eggs were incubated at an EST of 37.8°C from incubation day (E) 0 to E7. Thereafter, a 2 × 2 factorial arrangement with 2 EST (37.8°C and 38.9°C) from E8 to E14 and 2 EST (36.7°C and 37.8°C) from E15 till hatch was applied. After hatching, chickens were reared until slaughter age with the 4 EST treatments and 8 replicates per treatment. At day 41 and 42, one male chicken per replicate per day was selected, and hock burn and food pad dermatitis were scored. Rotated tibia, tibia dyschondroplasia, epiphyseal plate abnormalities, bacterial chondronecrosis with osteomyelitis, and epiphysiolysis were assessed. Tibia weight, length, thickness, head thickness, and robusticity index were determined. X-ray analyses (osseous volume, pore volume, total volume, volume fraction, mineral content, and mineral density) and a 3-point bending test (ultimate strength, yield strength, stiffness, energy to fracture, and elastic modulus) were performed. A high EST (38.9°C) in week 2 of incubation, followed by a normal EST (37.8°C) in week 3 resulted in higher mineral content (P = 0.001), mineral density (P = 0.002), ultimate strength (P = 0.04), yield strength (P = 0.03), and stiffness (P = 0.05) compared with the other 3 EST groups (week 2 × week 3 interaction). A high EST (38.9°C) in week 2 of incubation, regardless of the EST in week 3, resulted in a higher tibia weight (P < 0.001), thickness (P = 0.05), osseous volume (P < 0.001), and total volume (P < 0.001) than a normal EST (37.8°C). It can be concluded that 1.1°C higher EST than normal in week 2 of incubation appears to stimulate tibia morphological, biophysical, and mechanical characteristics of broiler chickens at slaughter age. Additionally, a 1.1°C lower EST in week 3 of incubation appears to have negative effects on tibia characteristics, particularly in interaction with the EST in week 2 of incubation.

Providing environmental enrichment for broilers is a potential strategy to increase welfare, activity, and health. The aim of this study was to evaluate the effect of environmental enrichment on health and leg bone characteristics of broilers. One control and 8 types of enrichment were included: 2 distances between food and water (7 and 3.5 m), roughage, vertical panels, straw bales, 2 platforms (30 and 5 cm), and a lowered stocking density (34 kg/m2). Birds were kept according to conventional Danish guidelines. The study included 58 pens with approximately 500 birds each. On day 35 of age, 25 birds per pen were killed and included in a postmortem analysis of wooden breast, body condition scores, pathological conditions (femoral head necrosis, arthritis, tenosynovitis, fractures, tibial dyschondroplasia, and twisted tibiotarsus), muscle width of the lower leg, and tibiotarsus properties (bone strength, weight, length, and proximal diameter, middle diameter, and distal diameter). It was predicted that environmental enrichment would have a positive effect on pathology with the exceptions that environmental enrichment that increased activity would pose a risk factor for wooden breast development, and straw bales would be a risk factor for bacterial infections (arthritis, tenosynovitis, and femoral head necrosis). Furthermore, it was hypothesized that enriched groups would have increased muscle width, bone strength, and dimensions of the tibiotarsus. Broilers with 7 m between food and water had a longer distal diameter of the tibiotarsus than those with straw bales (P = 0.04). The birds provided with vertical panels had wider leg muscle than the treatments with roughage (P = 0.045), 3.5 m distance (P = 0.049), and straw bales (P = 0.044). No effects were found for the remaining outcomes. These results suggest that provision of vertical panels and increased distance between resources can result in larger muscle and bone dimension, possibly having a positive effect on leg health. Furthermore, the provision of environmental enrichment does not appear to be a risk factor for wooden breast or bacterial infection.

Providing environmental enrichment for broilers is a potential strategy to increase welfare, activity, and health. The aim of this study was to evaluate the effect of environmental enrichment on health and leg bone characteristics of broilers. One control and 8 types of enrichment were included: 2 distances between food and water (7 and 3.5 m), roughage, vertical panels, straw bales, 2 platforms (30 and 5 cm), and a lowered stocking density (34 kg/m²). Birds were kept according to conventional Danish guidelines. The study included 58 pens with approximately 500 birds each. On day 35 of age, 25 birds per pen were killed and included in a postmortem analysis of wooden breast, body condition scores, pathological conditions (femoral head necrosis, arthritis, tenosynovitis, fractures, tibial dyschondroplasia, and twisted tibiotarsus), muscle width of the lower leg, and tibiotarsus properties (bone strength, weight, length, and proximal diameter, middle diameter, and distal diameter). It was predicted that environmental enrichment would have a positive effect on pathology with the exceptions that environmental enrichment that increased activity would pose a risk factor for wooden breast development, and straw bales would be a risk factor for bacterial infections (arthritis, tenosynovitis, and femoral head necrosis). Furthermore, it was hypothesized that enriched groups would have increased muscle width, bone strength, and dimensions of the tibiotarsus. Broilers with 7 m between food and water had a longer distal diameter of the tibiotarsus than those with straw bales (P 5 0.04). The birds provided with vertical panels had wider leg muscle than the treatments with roughage (P 5 0.045), 3.5 m distance (P 5 0.049), and straw bales (P50.044). No effects were found for the remaining outcomes. These results suggest that provision of vertical panels and increased distance between resources can result in larger muscle and bone dimension, possibly having a positive effect on leg health. Furthermore, the provision of environmental enrichment does not appear to be a risk factor for wooden breast or bacterial infection. [ABSTRACT FROM AUTHOR]

1. This trial investigated the effect of forced locomotor activity (training) on walking ability, leg posture, and growth performance, as well as carcass composition and meat quality in male fattening turkeys. 2. A flock of 744 commercial turkeys was divided into three experimental groups, either without any training period (control), training from weeks 2 to 8 (short-term), or training from weeks 2 to 21 (long-term). All birds were slaughtered at an age of 21 weeks. To study the effect of short vs. long time lapse between shackling and stunning (suspension time), each training group was split into two halves that were hooked on the shackle for either 15 s or 3 min prior to stunning. 3. Long-term physical training, compared to short-term or no training, resulted in better walking ability and in a lower percentage of leg malposition, as assessed at the end of fattening. No effect on final body weight was detected. 4. In a subsample, the composition of 80 carcasses was determined by dissection. Long-term training favoured the percentage of the drumstick over that of the breast cut in comparison to the group without any training. 5. Meat quality parameters were determined for breast muscle. The pH values 20 min post-mortem were reduced by long-term training, and the highest value was observed for a combination of no training with short suspension. After 24 h, pH values did not differ between experimental groups. The breast muscles were characterised as fast-glycolysing. Prolonged suspension time resulted in higher electrical conductivity after 24 h, and in higher a* values (redness). 6. In conclusion, the study revealed that a long-term training period improved walking ability and leg posture of heavy male turkeys. Thus, training can contribute to the improvement of animal welfare in turkey husbandry. Meat quality variables of breast muscles were partially influenced by locomotor activity and suspension time. [ABSTRACT FROM AUTHOR]

Increased prevalence of joint abnormalities at slaughter among pigs from organically certified herds in Sweden has been reported. Most of these abnormalities are caused by osteochondrosis, which has a genetic background. Thus, we investigated whether changing the sire breed from the commonly used Hampshire to the commercially available sire breed Duroc affected joint health and growth rate. We studied 766 commercially reared growing-finishing pigs from insemination of the mother sow until slaughter. The pigs were raised at four commercial organic farms (integrated or externally integrated, and had 40–160 sows in production) and slaughtered at one slaughter plant. We found no significant difference between the offspring of the two sire breeds regarding back conformation, leg conformation, swollen joints, locomotion or lameness at 13 or 24 weeks of age, or regarding joint abnormalities at slaughter. This indicates that clinical leg health will not be improved by changing sire breed. However, the Hampshire-sired pigs had higher daily growth rate (P < 0.008), allowing earlier slaughter. [ABSTRACT FROM AUTHOR]

Nowadays, there is much concern expressed about stocking density as it is related to the well-being and welfare of broilers, and to define some welfare aspects of broilers in an environmentally uncontrolled conventional house under two different densities, this experiment was conducted using a total number of 120 one day old Cobb broiler chicks that were randomly divided into two groups with three replicates of each in 6 floor pens (1m × 1.6 m). The first group (control) were housed at a density of 1000 cm2/ bird (16 birds/replicate/pen) while the second group (high density HD) were housed at a density of 666.66 cm2/ bird (24 birds/ replicate/pen). Results showed that litter quality was deteriorated (P˂0.05) at HD group especially at the 4th, 5th and 6th week of the growing cycle where the all quality parameter together were the worst. Additionally the incidence of the breast irritation and ammonia burns were greater at higher density group, moreover the severity was increased with limiting floor space due to worsening of the litter condition which adversely (P˂0.05) affect both leg strength as indicated by latency to lie test (LTL) and feather condition as indicated by plumage cleanliness score.

Highlights • Restricted lighting reduced TD incidence, and asymmetry along tibial length in broiler chickens. • High stocking density increased the incidence and severity of HB in broiler chickens. • Perching reduced the incidence and severity of FPD and HB in broiler chickens. Abstract An experiment was conducted to investigate the effects of lighting program, stocking density, and the provision of a perch on leg health variables as welfare indicators in broiler chickens. A total of 360 mixed sex Ross 308 1-D-old broiler chickens (180 male and 180 female) were placed in a completely randomized design with 2 × 2 × 2 factorial arrangement of lighting program (continuous or restricted), stocking density (12 or 18 birds/m2), and the provision of a perch (perch or without perch). At d 42, tibial dyschondroplasia (TD), valgus-varus deformity (VVD), footpad dermatitis (FPD), and hock burn (HB) were scored. In addition, tibio-tarsal index, robusticity index, bone weight-length index, tibia crude ash content, and fluctuating asymmetry (FA) and relative fluctuating asymmetry (rFA) of tibia width and length were measured. The incidence of TD increased in broiler chickens subjected to continuous lighting (P < 0.05) in comparison with those subjected to restricted lighting. Presence of a perch reduced the incidence and severity of FPD (P < 0.01) compared to without a perch. Restricted lighting tended (P = 0.093) to decrease the incidence and severity of HB lesions. The broiler chickens placed at low stocking density (12 birds/m2) and with access to a perch had lower incidence and severity of HB lesions (P < 0.01 and P < 0.001, respectively) compared to their corresponding opposite groups. Tibio-tarsal index was greater (P < 0.01) in broiler chickens subjected to restricted lighting regimen compared to continuous lighting whereas the provision of a perch tended to increase (P = 0.081) the tibio-tarsal index in broiler chickens compared to those without perch. There was a tendency of decreasing tibia crude ash content with increasing stocking density from 12 to 18 birds/m2 (P = 0.056). However, birds without perches had greater (P < 0.01) tibia crude ash content compared those with a perch provided. Continuous lighting increased the FA and rFA of tibia length in comparison with restricted lighting program (P < 0.05) in broiler chickens. In conclusion, it can be said that restricted lighting programs and provision of perches may help reduce the leg health problems thus contributing to improved welfare in broiler chickens. [ABSTRACT FROM AUTHOR]

Genetic selection for increased growth rate and muscle mass in broiler chickens has been accompanied by mobility issues and poor gait. There are concerns that the Pekin duck, which is on a similar selection trajectory (for production traits) to the broiler chicken, may encounter gait problems in the future. In order to understand how gait has been altered by selection, the walking ability of divergent lines of high- and low-growth chickens and ducks was objectively measured using a pressure platform, which recorded various components of their gait. In both species, lines which had been selected for large breast muscle mass moved at a slower velocity and with a greater step width than their lighter conspecifics. These high-growth lines also spent more time supported by two feet in order to improve balance when compared with their lighter, low-growth conspecifics. We demonstrate that chicken and duck lines which have been subjected to intense selection for high growth rates and meat yields have adapted their gait in similar ways. A greater understanding of which components of gait have been altered in selected lines with impaired walking ability may lead to more effective breeding strategies to improve gait in poultry.

The aim of this study was to assess the effect of providing environmental enrichment in the form of perches and string on the behaviour and welfare of commercial broiler chickens. Houses containing ~23 000 broiler chickens were assigned to one of four treatments in a 2×2 factorial design. Treatments involved two levels of access to perches (P) (present (24/house) ‘+P’ or absent ‘−P’) and two levels of access to string (S) (present (24/house) ‘+S’ or absent ‘−S’). All houses contained windows, and 30 straw bales were provided from day 10 of the rearing cycle. Treatments were applied in one of four houses on a single farm, and were replicated over four production cycles. Behaviour and leg health were observed in weeks 3 to 5 of the rearing cycle. Production performance and environmental parameters were also measured. There was an interaction between perches and age in the percentage of birds observed lying, with higher percentages of birds observed lying in the +P treatment than in the −P treatment during weeks 4 and 5. There was also a significant interaction between string and age in the percentage of birds observed in locomotion, with higher percentages observed in locomotion in the −S treatment than in the +S treatment during weeks 4 and 5. There was also an interaction between string and age in average gait scores, with lower gait scores in the +S treatment than in the −S treatment during weeks 3 and 5 but not within week 4. Daytime observations showed that perches and strings were used frequently, with one bout of perching occurring approximately every 80 s/perch, and one bout of pecking at string occurring every 78 s/string on average. There was a significant effect of age on use of perches (P

Footpad dermatitis is a condition that causes lesions on the plantar surface of the footpads in growing turkeys. Potential inflammatory processes and pain associated with increasing severity of footpad dermatitis raise animal welfare concerns. This study investigated whether the temperature of the plantar surface of the foot (the footpads and the entire plantar foot including interdigital membranes) assessed with infrared thermography reflects severity of mild footpad dermatitis as assessed with a Visual Analogue Scale in 80 turkey toms at 10 weeks of age. In order to study effects of a potential emotional arousal due to the testing procedures, effects of sequential testing order and duration of handling of the turkeys was included in the model. Footpad temperatures were significantly lower than foot temperatures (P < 0.001, R2 = 0.57, −3.36°C ± 0.28°C), and higher visual analogue scale scores were anti-correlated with footpad (−0.06°C ± 0.037°C) and foot temperatures (−0.07°C ± 0.066°C). Furthermore, a negative association between footpad temperature and handling time (−0.02 ± 0.0227, P = 0.048), and a non-linear association between foot and footpad temperatures and sequential testing order, were found (P<0.001). The results indicate that severity of mild footpad dermatitis as scored visually was associated with the temperatures of the plantar surface of the foot and footpads, and that thermal imaging therefore represents a novel tool for the reliable and non-invasive early detection of subclinical foot pathologies in turkeys. The association was negative, and the findings therefore indicate that potential inflammatory processes in the epidermis at this early stage of footpad dermatitis are negligible, and/or that the hyperkeratosis of the surface keratin shielded heat emission from the footpads. The associations between surface temperatures, handling time, and sequential testing order suggest an emotional arousal in response to the experimental procedures, and these factors need to be considered when applying infrared thermography in future studies of leg health in turkeys. [ABSTRACT FROM AUTHOR]

Two related experiments involving broiler chickens are presented. Experiment 1 evaluated the use of six perch types: (1) an A-frame design (incorporating a platform and ramps), (2) a ‘flat top’ ramp, (3) a curved ramp, (4) a suspended bar, (5) a fixed bar and (6) a suspended platform. Two of each perch type was provided in one commercial house on each of two farms over two 6-week production cycles. Each perch was videoed for a 24 h period in weeks 1–6 of cycle 1, and weeks 1–5 of cycle 2. Scan sampling was used to assign an occupancy score to different perch components (platform, bar and ramp, where appropriate), and an overall weighted occupancy score also calculated. Counts were made of perching and failed perching attempts following selected scans in cycle 1. There were significantly higher occupancy scores for platform than for bar or ramp components, and this was apparent across the production cycle. This resulted in a higher overall weighted occupancy score for suspended platforms. The percentage of failed perching attempts was significantly greater with fixed and suspended bar perches than with the curved ramp. Three treatments were assessed in Experiment 2: (1) provision of six suspended platform perches (P), (2) provision of six suspended platform perches and four peat-filled dust baths (PD), and (3) control treatment with no platform perches or dust baths. Treatments were applied in one of three houses on each of two farms, and replicated over three cycles. Two perches in each of the P and PD treatments were videoed for a 25 min period in weeks 3, 4 and 5, and number of birds using the perches recorded. The severity of angular leg deformities, hock burn and pododermatitis lesions, and walking ability were scored in weeks 3, 4 and 5, and prevalence of pododermatitis and hock burn recorded at slaughter. Litter moisture and production-related measures were also taken. On average, 26 birds (12.6 birds/m 2 ) occupied the perches, and this was not affected by provision of dust baths or age. Treatment did not significantly affect any of the measures taken. It is concluded that broilers prefer to perch on platforms rather than bars or ramps, and thus that platforms better cater for an important behavioural need. However, provision of platform perches, even in combination with dust baths, did not improve leg health, and future research should investigate greater levels of provision of these enrichments. [ABSTRACT FROM AUTHOR]

The use of straw bales as an environmental enrichment is common for broiler chickens in enriched housing systems, however relatively little information exists about their effectiveness in improving welfare. There has also been no widespread introduction of a dustbathing material for broilers. The main aim of this trial was to evaluate the use of a dustbathing substrate (in the form of oat hulls), both as an alternative to straw bales and as a supplementary enrichment. Over four replicates, four commercial houses, each containing approximately 22,000 broilers, were assigned to one of four treatments over the 6-week production cycle: (1) straw bales (B; one per 155 m 2 ), (2) oat hulls as a dustbathing substrate (OH; provided in 1 m diameter steel rings, one per 155 m 2 ), (3) both oat hulls and straw bales (OH + B), and (4) a control treatment with no environmental enrichment (C). Observations of broiler behaviour and leg health were taken weekly, and performance data was collected for each cycle. Broilers housed in the OH and OH + B treatments had better gait scores in week 6 than those housed in the C treatment ( P < 0.05), which suggests that the provision of oat hulls improved bird leg health. However, there was no associated increase in activity levels in unenriched areas of the houses. Conversely, more locomotion ( P < 0.001), less sitting inactive ( P < 0.001) and less sitting pecking ( P < 0.001) were observed in the C treatment than in unenriched areas of B, OH and OH + B treatments. More birds were recorded around the bales compared to the oat hulls ( P < 0.001), however birds performed significantly more foraging ( P = 0.019) and dustbathing ( P = 0.045) in oat hulls than around straw bales. Although oat hulls appear to be more suitable for stimulating active behaviours than straw bales, the high level of resting recorded around the bales suggests they may have a positive function as protective cover. The presence of an additional type of enrichment in the house did not affect the number of birds, or the type of behaviours performed in close proximity to either straw bales or oat hulls ( P > 0.05). Treatment did not have a significant effect on pododermatitis levels or slaughter weight, on mortality rates, or on litter quality or atmospheric ammonia levels ( P > 0.05). Overall, our results suggest that the oat hulls substrate was a successful enrichment in terms of promoting dustbathing and foraging, and improving bird leg health. The straw bales also appeared attractive to the birds, however, which suggests that a dustbathing substrate should be a supplementary enrichment. [ABSTRACT FROM AUTHOR]

The study herein investigated the effect of mean particle size, calcium (Ca) source, Ca concentration and phytase on broiler performance, mineral digestibility and skeletal integrity from 1 to 28 days post-hatch. Sixteen dietary treatments were arranged in a 2 · 2 · 2 · 2 factorial design consisting of two Ca sources (limestone or a highly soluble calcium, HSC), two Ca concentrations (9.0 or 6.0 g/kg from Day 0 to Day 14 and 8.0 or 5.5 g/kg from Day 15 to Day 28), two Ca particle sizes (<0.5 or >0.5 mm) and two phytase-supplementation levels (0 or 1000 FTU/kg). Overall performance (Days 1-28) showed that the addition of phytase to diets containing 8.0 g/kg total Ca provided by HSC improved feed intake (P < 0.05), but there was no effect of the addition of phytase to birds fed Ca from limestone. Phytase supplementation decreased feed intake in birds fed limestone with a mean particle size >0.5 mm and increased feed intake in birds fed HSC with a mean particle size >0.5 mm, which resulted in a Ca sourceCa particle size · phytase interaction (P < 0.05). Birds fed diets containingHSChad a lower liveweight gain than did birds fed diets containing limestone (P=0.03). Increasing the dietary Ca concentration from 5.5 g/kg to 8.0 g/kg total Ca decreased liveweight gain (P = 0.01). Phytase supplementation increased final liveweight gain (P < 0.001). Foot ash was observed to be higher in birds that received diets containing 8.0 g/kg Ca (P < 0.05). Phytase supplementation increased foot ash percentage (P < 0.05). Phytase increased Ca digestibility in birds fed diets containing Ca provided by HSC with a mean particle size <0.5 mm and diets containing limestone with a mean particle size >0.5 mm (P < 0.05). Phytase increased Ca digestibility in birds fed 5.5 g/kg Ca, but had no effect on Ca digestibility in birds fed 8.0 g/kg Ca (P < 0.05). The addition of phytase to diets improved the digestibility of phosphorus, especially in birds fed diets containing limestone (P < 0.05), or 8.0 g/kg total Ca (P < 0.05), or diets with a mean particle size >0.5 mm (P < 0.05). The results of the present study are consistent with those of previous studies by the authors, which have shown that low dietary Ca in conjunction with phytase improves broiler performance and mineral digestibility. Phytase improved growth performance, regardless of Ca source or Ca concentration and improved mineral digestibility. [ABSTRACT FROM AUTHOR]

Inactivity and leg disorders negatively impact broiler welfare. Enrichment designed to increase barn complexity may encourage physical exercise. The study aim was to implement a second-generation laser enrichment device, previously shown to increase broiler activity, for extended periods of time and to measure behavior and tibia quality. A total of 1,360 Ross 708 broilers in 40 pens of 34 were assigned to laser enrichment or control (no laser enrichment) for 49 d. Seventy focal birds were randomly selected on d 0 for individual behavior analysis. Laser-enriched birds were exposed to 6-min laser periods 4 times daily. A 3-min novel object test was performed on all pens and tonic immobility was induced on 1 bird/pen on wk 1 and 6. Focal bird time budget and walking distance and pen-wide laser-following behavior and movement were obtained during laser periods d 0 to 8 and 1 d/wk through wk 7. Right tibias were collected from focal birds on d 49 for dual energy x-ray absorptiometry and bone breaking analysis. Time spent active during laser periods was increased on d 3, 6, and 8 and wk 2 to 3 in laser-enriched vs. control focal birds (P = 0.04). Time at the feeder was increased in laser-enriched focal birds on d 0, 3 to 4, and 8 and wk 2 and 4 (P < 0.01). Distance walked during laser periods was increased in laser-enriched focal birds on d 1, 3 to 5, 8, and wk 2 compared to the control (P < 0.01). Pen-wide movement was increased on d 0, 2, 4 to 8, and wk 1 to 5 and 7 in laser-enriched vs. control birds (P < 0.01). More laser-enriched broilers were within 25 cm of the novel object at 1 min 30 s than the control (P = 0.03), and latency to approach the novel object was reduced in both treatments at wk 6 compared to wk 1 (P < 0.01). Tonic immobility duration was increased by 123 s on wk 6 compared to wk 1, regardless of treatment (P < 0.01). Daily laser enrichment for extended periods increased bird activity without inducing fearfulness or altering tibia measures. [ABSTRACT FROM AUTHOR]

With the overselection of broiler body weight (BW) and breast muscle weight (BMW), the incidence of leg disease has been gradually increasing, which has seriously affected the welfare and industrial economic development of broilers. In this study, we used gait score and X-ray to evaluate the leg health of fast large white-feather broiler chickens at the age of 6 to 7 wk. The combined use of the 2 methods improved the detection rate and accuracy of diagnosing chicken leg disease. Moreover, more than 70% of chickens with abnormal gait scores also appeared abnormal on X-ray. At the same time, the 40-day BW, 42-day BMW, 28- to 40-day body weight gain (BWG) and tibial bone strength (BS) of the abnormal broilers were significantly lower than those of normal chickens. The 28- to 40-day feed conversion rate (FCR) significantly increased relative to normal chickens (P < 0.05). The comprehensive application of this method would be more suitable for evaluating of commercial broiler leg diseases, and providing a more complete set of in vitro evaluation criteria for broiler leg diseases. [ABSTRACT FROM AUTHOR]

This study aimed to assess the effect of the number of straw bales (SBs) provided on the behaviour and leg health of commercial broiler chickens. Houses containing ~23 000 broiler chickens were assigned to one of two treatments: (1) access to 30 SBs per house, ‘30SB’ or (2) access to 45 SB per house, ‘45SB’. This equated to bale densities of 1 bale/44 m2 and 1 bale/29 m2 of floor space within houses, respectively. Treatments were applied in one of two houses on a commercial farm, and were replicated over six production cycles. Both houses had windows and were also artificially lit. Behaviour was observed in weeks 3 to5 of the cycle. This involved observations of general behaviour and activity, gait scores (0: perfect to 5: unable to walk) and latency to lie (measured in seconds from when a bird had been encouraged to stand). Production performance and environmental parameters were also measured. SB density had no significant effect on activity levels (P>0.05) or walking ability (P>0.05). However, the average latency to lie was greater in 30SB birds compared with 45SB birds (P0.05). The results from this study suggest that increasing SB levels from 1 bale/44 m2 to 1 bale/29 m2 floor space does not lead to significant improvements in the welfare of commercial broiler chickens in windowed houses.

Free-range access for broiler chickens can benefit animal welfare because the birds have access to a more natural environment and more opportunities to perform natural behaviours than in indoor systems. Also, they have more space and more environmental enrichment, which could lead to better leg health and decreased fearfulness. In practice, however, use of the free-range area is often low. Lack of shelter likely plays an important role in this, as do weather conditions. In this study during 2 production rounds of slow-growing broiler chickens, 200 chickens were housed indoors (IN), 200 were provided with free-range access to grassland with artificial shelter (AS), and 200 were provided with free-range access to an area with short rotation coppice (SRC) from 4 until 10 weeks of age. Free-range use was monitored using photographs and live observations. Weather conditions and free-range use were monitored throughout the outdoor period. Tonic immobility (TI) as fearfulness assessment was done at the beginning (round 2 only) and the end of both production rounds; leg health and tibia bone health were assessed at the end of the production rounds. Mean percentage of birds using the free-range area was higher in SRC than in AS groups (42.8% vs. 35.1%; F 1,7 = 1180.00, P < 0.001). The mean percentage of animals located further than 5 m from the house was 10.6 ± 1.1% of the chickens that were outside in the SRC groups vs. 4.1 ± 0.8% in the AS groups (F 1,7 = 24.03, P = 0.002). The interactions of shelter type with rainfall (F 2,5578 = 70.59, P < 0.001), increasing radiation (F 2,5578 = 300.93, P < 0.001) and increasing wind speed (F 2,5578 = 14.77, P < 0.001) showed that these factors were related with fewer chickens being outside; and that these effects were more pronounced in SRC than in AS chickens. An increasing temperature was related with more free-range use (F 1,5578 = 32.24, P < 0.001). A shorter TI duration in week 3 (at group level) was associated with more chickens further than 5 m from the house (F 1,250 = 13.79, P < 0.001). The percentage of animals needing more than one induction to induce TI in week 10 was higher for chickens from SRC (29.7%) than from IN groups (4.8%; t 102 = −2.61, P = 0.028) but not AS (14.8%). Hock dermatitis occurred less in AS (7.6%) than in IN (40.1%; t 222 = 3.15, P = 0.005) but not SRC (13.7%). These findings indicate that presence of SRC was most effective in encouraging chickens to use the free-range area, but that free-range access was only moderately related to better leg health and fearfulness (at group level). [ABSTRACT FROM AUTHOR]

The aims of this study were to estimate the genetic parameters for leg and foot health and mobility in purebred turkey lines and their genetic correlations with BW. Traits were gait score (GS) as an overall measure of leg health, footpad dermatitis (FPD), and 2 skeletal leg health traits, namely, valgus and varus deformities (VVD) and tibial dyschondroplasia (TD). Data from 4 different lines, comprising 3 yr of phenotypic records and 4 yr of pedigree information per line, were used. The sex average BW for the lines at 18 wk ranged from 19.1 kg (line A) to 12.4 kg (line D). The prevalence of VVD ranged from 5.2 to 14.6% and for TD from 4.1 to 23.2%. The average score for FPD on a scale of 0 to 100 ranged from 48.5 to 61.1. Gait Score was scored on a scale of 1 to 5, standardized to a mean of 3 and SD of 1. Heritabilities were estimated at 0.08 to 0.13 for GS, 0.01 to 0.07 for VVD, 0.06 to 0.12 for TD, and 0.10 to 0.15 for FPD (all SE ≤ 0.02). Estimates of the genetic correlations between VVD and TD ranged from 0.03 to 0.21 (all SE ≤ 0.08), and estimates of these with GS ranged from 0.07 to 0.87 (all SE ≤ 0.09). The genetic correlations of FPD with GS ranged from 0.00 to 0.34 (all SE ≤ 0.04), and with the skeletal leg health traits from -0.06 to 0.33 (all SE ≤ 0.06). Body weight showed estimated genetic correlations ranging from 0.28 to 0.51 (all SE ≤ 0.06) with GS, -0.06 to 0.50 (all SE ≤ 0.13) with VVD/TD and 0.05 to 0.34 (all SE ≤ 0.05) with FPD. The results suggest that selection for improved leg health can be incorporated effectively in a commercial turkey breeding program using balanced breeding goals, in which production traits and leg health traits are considered simultaneously. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the effect of natural light and straw bales on activity levels and leg health in commercial broiler chickens. Houses containing ∼23 000 broiler chickens were assigned to one of four treatments in a 2 × 2 factorial design. Treatments involved two levels of access to natural light (NL) (present ‘+NL’, or absent ‘−NL’) and two levels of access to straw bales (SB) (present (30/house) ‘+SB’, or absent ‘−SB’). All houses were windowed and artificially lit, and windows were shuttered where appropriate. Treatments were applied in one of the two houses on each of the two farms, and were replicated over four production cycles. Behaviour was observed in 2 to 6 weeks of the cycle. This involved observations of general behaviour and activity, gait scores (0 (perfect) to 5 (unable to walk)) and latency to lie (measured in seconds from encouraging a bird to stand). Production performance and environmental parameters were also measured. Average daytime light intensity and UV levels in the +NL treatment were 85.2 lx and 3.37 μW/cm2, respectively, and in the −NL treatment were 11.4 lx and 0 μW/cm2, respectively. Litter moisture levels were lower with NL treatment (P < 0.05), but were not affected by SB (P > 0.05). The percentage of time spent lying was significantly reduced by the provision of NL (P < 0.01), but not by SB (P > 0.05). There were three-way interactions between NL, SB and bird age on the percentage of time spent in locomotion (P < 0.05) and idling (P < 0.05). Both treatment factors had inconsistent effects on these parameters across different weeks. Levels of preening, resting and aggressive behaviour were not affected by treatment (P > 0.05). There was an interaction between treatments in average gait scores, with higher scores in the −NL−SB treatment than in all other treatments, and higher in the −NL+SB treatment than in the +NL treatments (P < 0.001). Average latency to lie was significantly higher with NL (P < 0.001) and SB (P < 0.05). We conclude that environmental modifications have the potential to increase activity levels and improve the leg health of commercial broilers. The light environment appears to be particularly important in this respect.

Gait scoring is the most popular method for assessing the walking ability of poultry species. Although inexpensive and easy to implement, gait scoring systems are often criticized for being subjective. Using a treadmill performance test we assessed whether observable differences in Pekin duck walking ability identified using a gait scoring system translated to differences in walking performance. One hundred and eighty ducks were selected using a three-category gait scoring system (GS0 = smooth gait, n = 55; GS0.5 = labored walk without easily identifiable impediment, n = 56; GS1 = obvious impediment, n = 59) and the amount of time each duck was able to sustain walking on a treadmill at a speed of 0.31 m/s was evaluated. The walking test ended when each duck met one of three elimination criteria: (1) The duck walked for a maximum time of ten minutes, (2) the duck required support from the observer's hand for more than three seconds in order to continue walking on the treadmill, or (3) the duck sat down on the treadmill and made no attempt to stand despite receiving assistance from the observer. Data were analyzed in SAS 9.4 using PROC GLM. Tukey's multiple comparison test was used to compare differences in time spent walking between gait scores. Significant differences were found between all gait scores (P < 0.05). Behavioral correlates of walking performance were investigated. Video recorded during the treadmill test was analyzed for counts of sitting, standing, and leaning behaviors. Data were analyzed in SAS 9.4 using a negative binomial model for count data. No differences were found between gait scores for counts of sitting, standing, and leaning behaviors (P > 0.05). In conclusion, the amount of time spent walking on the treadmill corresponded to gait score and was an effective measurement for quantifying Pekin duck walking ability. The test could be a valuable tool for assessing the development of walking issues or the effectiveness of treatments aimed at promoting leg health. [ABSTRACT FROM AUTHOR]

Injurious pecking in turkeys is a serious welfare and economic concern in commercial production. Yet, very little is known about the development of this behaviour, and whether it relates to physical characteristics of the turkey. The objective of this study was to investigate the relationships among group variation in body weight, snood length, leg health, and skin and plumage damage over time in adult male turkeys. At 11 weeks of age, 50 male turkeys were allocated to one of three treatments based on body weight: HEAVY (8.22 ± 0.11 kg), AVERAGE (7.54 ± 0.11 kg), or LIGHT (7.14 ± 0.11 kg; mean ± standard error of the mean (SEM)). Turkeys were housed in groups of 8–10 with two replicates per treatment. They were weighed and scored weekly for plumage and skin condition (separate scores for head, neck, back, wings, and tail) and leg health (gait, footpad health and cleanliness, and number and severity of deviated toes). The data were divided into three time periods: 11–13, 14–17, and 18–21 weeks of age, and analyzed with a mixed model procedure and principal components analysis in SAS. With time, gaits worsened (Live Gait: F 2,65 = 14.72, P < 0.0001, Video Gait: F 2,43 = 2.00, P = 0.15) and turkeys had more deviated toes (F 2,71 = 177.10, P < 0.0001) and a greater severity of toe deviations (F 2,112 = 75.15, P < 0.0001) across all weight treatments. All turkeys showed worse footpad cleanliness over time (F 2,162 = 12.01, P < 0.0001), which might have contributed to the increase in footpad health problems (F 2,69 = 15.58, P < 0.0001). Pecking injuries to the head (F 1,66 = 17.71, P < 0.0001) and neck (F 1,46 = 4.40, P = 0.042) became more prevalent after the first period, whereas pecking injuries to the back (t 48 = −4.37, P < 0.0001) increased in the final period. Damage to the tails of these turkeys also increased significantly in the final period (t 51 = −6.80, P < 0.0001). Snood length did not vary between treatments and showed no association to the head and neck condition of these turkeys. As turkeys aged, signs of injurious pecking increased while leg health deteriorated. However, group variation in early body weights was not predictive of leg health, snood length, or being the recipient of skin and plumage damage later in life. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the effect of providing environmental enrichment in the form of perches and string on the behaviour and welfare of commercial broiler chickens. Houses containing ~23 000 broiler chickens were assigned to one of four treatments in a 2×2 factorial design. Treatments involved two levels of access to perches (P) (present (24/house) ‘+P’ or absent ‘−P’) and two levels of access to string (S) (present (24/house) ‘+S’ or absent ‘−S’). All houses contained windows, and 30 straw bales were provided from day 10 of the rearing cycle. Treatments were applied in one of four houses on a single farm, and were replicated over four production cycles. Behaviour and leg health were observed in weeks 3 to 5 of the rearing cycle. Production performance and environmental parameters were also measured. There was an interaction between perches and age in the percentage of birds observed lying, with higher percentages of birds observed lying in the +P treatment than in the −P treatment during weeks 4 and 5. There was also a significant interaction between string and age in the percentage of birds observed in locomotion, with higher percentages observed in locomotion in the −S treatment than in the +S treatment during weeks 4 and 5. There was also an interaction between string and age in average gait scores, with lower gait scores in the +S treatment than in the −S treatment during weeks 3 and 5 but not within week 4. Daytime observations showed that perches and strings were used frequently, with one bout of perching occurring approximately every 80 s/perch, and one bout of pecking at string occurring every 78 s/string on average. There was a significant effect of age on use of perches (P<0.001) and string (P<0.001), with perching peaking during week 5 and string pecking peaking during week 3. We conclude that commercial broilers in windowed houses with access to straw bales display an interest in additional enrichment stimuli in the form of perches and string, and therefore that these stimuli have the potential to improve welfare. In addition, provision of string as a pecking device appeared to positively influence walking ability. However, this effect was numerically small, was only shown in certain weeks and was not reflected in the other leg health measure (latency to lie). The results also showed an apparent negative effect of string and perches on the activity levels of birds (recorded away from the immediate vicinity of these enrichments) towards the end of the production cycle. These results emphasise the need for further research into optimum design and layout of enrichment stimuli for modern broilers in windowed houses to ensure that their provision leads to clear welfare benefits. [ABSTRACT FROM PUBLISHER]