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The northern fowl mite (Ornithonyssus sylviarum) is a key pest for caged laying hens. High infestation levels can lead to anemia, reduced production, and mortality. Although the mites cause skin irritation and thus likely affect resting behavior, the nocturnal behavior of infested chickens has not yet been studied. We investigated the impact of mite infestation on nighttime behavior of 16 beak-trimmed White Leghorn hens. The hens were housed individually in wire cages. They were experimentally inoculated with approximately 35 mites at 25 weeks of age and observed for the behaviors dozing, sleeping, preening and being active. Continuous observations were made from video recordings taken from 22:00 h until 06:00 h for two consecutive nights at pre-infestation week 0 and post-infestation weeks 3, 5 and 7. Mite infestation levels were measured weekly on an 8-point scale (0 (no mites) to 7 (≥10,000 mites per hen)). For statistical analyses with linear mixed models, mite infestation levels were categorized as score 0 (no mites), 3–4 (51–500), 5 (501–1000) and 6–7 (>1000). Higher levels of mite infestation were associated with hens spending less time dozing (P < 0.001) and more time preening (P < 0.001) and being active (P = 0.012). Dozing decreased from 90% of the observed time for mite score 0 to 76% for score 6–7. Preening increased from 2% (score 0) to 9% (6–7) and time spent being active increased from 1% (0) to 7% (6–7). Mite infestation increased the number of uninterrupted bouts of all behaviors (P ≤ 0.020), especially dozing and preening (P < 0.001), suggesting restlessness in the mite-infested hens due to irritation and itching. The mite-infested hens’ increased nocturnal activity, including preening, as well as the fragmentation of behavioral activities together with decreased dozing, indicate disturbed resting behavior and suggest a reduction in the welfare of mite-infested hens.

Understanding the affiliative social relationships, or bonds, between zoo elephants has implications for both their welfare and management, yet there is limited work assessing and describing these bonds. Consequently, there is a need for the development of a reliable assessment tool. We used multiple metrics of proximity and tactile contact, as well as keeper surveys, to assess the social bond strength of 41 elephant dyads from 22 different zoos. Survey descriptions of social bond strength were based on previous research and included proximity and separation-reunion behaviors between individuals in a dyad. Approximately half of the elephant dyads in our study were rated as having a “strong” or “strongest” bond by keepers, who showed excellent agreement in their ratings of elephant bond strength (ICC(1,k) = 0.82). Elephant dyads that spent more time in proximity (within two elephant body lengths), and those that were more consistent in this behavior across time had an increased predicted probability of being rated as having a “strong or strongest bond” by keepers (p

Environmental stimuli present during incubation can impact the behavior of birds post-hatch. To determine the effect of exposing broiler chicken embryos to light on fear-related behavior post-hatch, we conducted two experiments in which we incubated eggs under various light schedules, and then measured fear responses when the chickens (N = 720) were 3–6 wk of age. In Expt. 1, the incubation photoperiods were 0L:24D, 12L:12D, and 24L:0D, and tonic immobility (TI) and inversion (INV) tests were administered. In Expt. 2, the incubation photoperiods were 0L:24D, 1L:23D, 6L:18D, and 12L:12D; and an approach test (APPR) and an emergence (EMRG) test were administered in addition to TI and INV. In Expt. 1, both 12L:12D and 24L:0D had shorter latencies to right during TI (213.5 ± 23.7 and 231.8 ± 24.2 s, respectively) than 0L:24D (305.5 ± 26.1 s) and also wing flapped less intensely during INV (12L:12D 5.0 ± 0.1 wing flaps; 24L:0D 5.4 ± 0.2) than 0L:24D (5.7 ± 0.1). In Expt. 2, the 12L:12D birds once again had shorter latencies to right during TI (120.0 ± 16.5 s) and wing flapped less intensely during INV (4.7 ± 0.1 wing flaps) than 0L:24D (201.4 ± 24.9 and 5.5 ± 0.1, respectively). They also had shorter latencies to exit the dark box in EMRG (28.9 ± 3.3 s), and were less active (28 ± 2%), vocalized less (178.8 ± 9.3 times/3 min) and spent more time closer to the observer during APPR (63 ± 3%) than 0L:12D (42.9 ± 5.0 s, 35 ± 3%, 211.2 ± 10.4 times/3 min, 51 ± 3). The 1L:23D and 6L:18D showed some reductions in fearfulness compared to 0L:24D, but these were not consistent across tests. The 6L:18D and 12L:12D birds demonstrated lateralization in the direction to leave the box in EMRG, whereas 1L:23D and 0L:12D exited left or right at chance levels. The results of these experiments indicate that providing at 12 h of light stimulation daily during embryogenesis results in long-term reductions in fearfulness as measured by multiple tests, and that this may be related to cerebral lateralization. In conjunction with other research, these findings show that light exposure during embryogenesis has important implications for behavioral phenotypes and welfare in chickens.

Chickens provided with outdoor access often do not fully use the range area. Natural cover, such as trees, can provide shelter and increase range use, but may not be practical for use in all free-range operations. A study was conducted to determine whether constructed enrichments that simulate natural structures increase range use and impact behavior of meat chickens. Slow-growing Delaware chickens were raised in floor pens (17 birds/pen) in a naturally ventilated house, with a pophole in each pen that allowed daily access to a vegetation-covered outdoor area. Feed and water were provided inside and outside. Birds were randomly assigned to one of 2 treatments: no range enrichment (control; NON) or range enrichment (ENR), which had roosts made of plastic pipe or screened shelters placed 7.6 m and 22.9 m from the house and overhead shade panels at 15.2 m. There were 4 replications. The numbers of birds inside and in the 4 quadrants of the range were counted in 7-min intervals 3 times daily (0900 h, 1300 h, and 1600 h) for 3 consecutive d when the birds were 7 and 10 wk of age; the numbers of birds performing various behaviors also were counted. On average, only 12.9% of birds used the range at any given time. The behavior of the birds was strongly affected by location (inside vs. outside), with birds mainly foraging and walking while outside and feeding, standing, and sitting while inside. Time of d impacted the number of birds that ranged (P ≤ 0.0001), with fewest birds outside during mid-day. Overall, birds using the range were most often (71%) observed in the quadrant nearest the house (zero to 7.6 m). However, in the ENR treatment, more birds (13%; P ≤ 0.0001) were observed in the farthest 2 quadrants (15.2 to 30.5 m from the house) than in the NON treatment (6%). This indicates that adding constructed enrichments to the range encouraged meat chickens to use it more fully.

The growing emphasis on ensuring the sustainability of animal agriculture is providing an impetus for the adoption of new approaches to structuring and conducting research. Sustainability is a complex topic involving many considerations related to the economic, social, and environmental impacts of production systems. Successfully addressing this topic requires multidisciplinary research as well as a high degree of communication with food system stakeholders to ensure that the research results contribute to informed decision making. In this paper, we provide an overview of a public-private partnership, the Coalition for Sustainable Egg Supply (CSES), which was formed to support research evaluating the sustainability of laying hen housing systems. Because of increasing public concerns about the behavioral restriction imposed on laying hens housed in conventional cages, the U.S. egg industry is faced with a need to transition to alternative systems. However, before the CSES project, there was limited information available about how this transition might affect trade-offs related to the sustainability of egg production. The goal of the CSES project was to provide this information by conducting holistic research on a commercial farm that had 3 different hen housing systems. The CSES members represented a variety of stakeholders, including food retailers and distributors, egg producers, universities, and governmental (USDA ARS) and nongovernmental organizations. The CSES was facilitated by a not-for-profit intermediary, the Center for Food Integrity, which was also responsible for communicating the research results to food system stakeholders, including via quantitative and qualitative consumer research. In this paper, we describe the structural aspects of the CSES that were responsible for the successful completion and dissemination of the research as well as the insights that were gained regarding multidisciplinary and multi-institutional collaboration, conducting commercial-scale research, fostering and maintaining stakeholder interaction, and communicating research results. Although not without limitations, this project demonstrates that public-private partnerships can be effective strategies for addressing sustainability questions related to animal agriculture and, thus, serves as a useful model for the other animal industries.

The effects of beak condition on ectoparasite populations and preening in laying hens were investigated. Beak-trimmed and beak-intact caged Hy-Line W-36 hens were infested with either chicken body lice or northern fowl mites using a 2 × 2 factorial design with 4 replicate cages (each containing 2 hens)/treatment: 1) BTL (beak-trimmed lice-infested); 2) BTM (beak-trimmed mite-infested); 3) BIL (beak-intact lice-infested); and 4) BIM (beak-intact mite-infested). Mite scores and lice numbers were estimated weekly. Hens were video recorded the wk before infestation and at wk 6 and 9 post-infestation. Time spent preening on 6 body areas and in total were analyzed using a repeated measures ANOVA. There was a wk × beak condition interaction for lice loads, with BTL harboring approximately 17 times more lice than BIL from wk 7 to 10 post-infestation (P < 0.0001). Beak condition affected mite loads (P < 0.0001), with BTM having a higher mite score (3.8 ± 0.26) than BIM (1.4 ± 0.26). At peak infestation, BTL spent more total time preening (P = 0.02, s ± SE: 232.1 ± 37.6) than prior to infestation (33.9 ± 37.6) and directed their preening behavior towards the vent. In contrast, BIL (73.9 ± 37.6), BTM (9.4 ± 1.6), and BIM (8.6 ± 1.6) did not increase total time spent preening over pre-infestation levels (103.6 ± 37.6, 5.8 ± 1.6, 6.7 ± 1.6 respectively), although BTM did redirect their preening behavior toward the vent. This study confirmed previous studies showing that an intact beak is important for reducing ectoparasite infestations. Preening behavior increased in response to lice infestation, but only in beak-trimmed hens; preening behavior and louse load were correlated at peak infestation. In contrast, mite infestation did not lead to increased preening, and there was no correlation between preening and mite load. However, both lice- and mite-infested hens directed preening behavior predominantly towards the vent where these parasites are typically found.

This paper is an integral part of the special publication series that arose from the multidisciplinary and multi-institutional project of the Coalition for Sustainable Egg Supply (CSES). The CSES project involves 3 housing systems for egg production at the same research farm site in the Midwest, USA, namely, a conventional cage (CC) house, an aviary (AV) house, and an enriched colony (EC) house. The CC house (141.4 m L × 26.6 m W × 6.1 m H) had a nominal capacity of 200,000 hens (6 hens in a cage at a stocking density of 516 cm2/hen), and the cages were arranged in 10 rows, 8 tiers per cage row, with a perforated aisle walkway at 4-tier height. The AV house (154.2 m L × 21.3 m W × 3.0 m H) and the EC house (154.2 m L × 13.7 m W × 4.0 m H) each had a nominal capacity of 50,000 hens. The AV house had 6 rows of aviary colonies, and the EC house had 5 rows of 4-tier enriched colonies containing perches, nestbox, and scratch pads (60 hens per colony at a stocking density of 752 cm2/hen). The overarching goal of the CSES project, as stated in the opening article of this series, was to comprehensively evaluate the 3 egg production systems from the standpoints of animal behavior and well-being, environmental impact, egg safety and quality, food affordability, and worker health. So that all the area-specific papers would not have to repeat a detailed description of the production systems and the management practices, this paper is written to provide such a description and to be used as a common reference for the companion papers.

In 2012, the World Organisation for Animal Health adopted 10 'General Principles for the Welfare of Animals in Livestock Production Systems' to guide the development of animal welfare standards. The General Principles draw on half a century of scientific research relevant to animal welfare: (1) how genetic selection affects animal health, behaviour and temperament; (2) how the environment influences injuries and the transmission of diseases and parasites; (3) how the environment affects resting, movement and the performance of natural behaviour; (4) the management of groups to minimize conflict and allow positive social contact; (5) the effects of air quality, temperature and humidity on animal health and comfort; (6) ensuring access to feed and water suited to the animals' needs and adaptations; (7) prevention and control of diseases and parasites, with humane euthanasia if treatment is not feasible or recovery is unlikely; (8) prevention and management of pain; (9) creation of positive human-animal relationships; and (10) ensuring adequate skill and knowledge among animal handlers. Research directed at animal welfare, drawing on animal behaviour, stress physiology, veterinary epidemiology and other fields, complements more established fields of animal and veterinary science and helps to create a more comprehensive scientific basis for animal care and management.

The increasing separation of the public from production agriculture means there is often a lack of knowledge among consumers about current production practices and a perception that increased productivity and economic efficiency are necessarily associated with a decline in animal welfare. A symposium was organized to present information about animal welfare issues and the challenges they pose for both scientists and the poultry and allied industries. Companion papers provide information about understanding public attitudes and physiological/immunological approaches to welfare assessment, while this paper outlines current and future challenges to egg and meat production and industry responses to those challenges. For broiler chickens, increases in growth rate result in corollary increases in metabolic heat generation and water consumption, leading to the need for continuing improvements in housing, ventilation, and litter management. Stocking densities, lighting programs, muscle myopathies, and use of antibiotics are also areas that require research attention. In the layer industry, the key challenge is housing, with the industry undergoing a shift from conventional cage housing to alternatives like enriched colonies or cage-free. While these alternative systems have hen welfare advantages, there are also welfare disadvantages that require the development of mitigation strategies, and it is also essential to address associated issues including economic, environmental, egg safety, and worker health impacts. Concerns on the horizon include euthanasia of surplus male chicks and spent hens as well as beak-trimming. The humaneness of slaughter methods is an important welfare and consumer confidence issue, and the current regulations for poultry slaughter in the USA are discussed and compared to those for livestock. The poultry and allied industries, including retailers, are responding to these concerns by consulting with experts, developing science-based animal care standards and auditing programs, strengthening training and oversight programs, promoting research, and improving communication channels. In future, intensifying multi-disciplinary research efforts and developing mechanisms to improve communication between scientists and stakeholders, including the public, will be critical to addressing these issues.

SUMMARY The United Egg Producers husbandry guidelines for cages recommend a minimum of 432 to 555 cm 2 (67 to 86 in. 2 ) of usable space/hen, defined as floor space that is of sufficient height for hens to stand upright. Because there is neither a quantitative value given for cage height nor an established method for calculating usable space, meeting this guideline poses challenges for producers. The objectives of this study were to design a tool that could be used to calculate usable space and evaluate the effect of cage height on that space. Based on some reported hen behavior, it has been suggested that cage height should be at least 35.6 to 40.6 cm (14 to 16 in.), the effect of these height specifications on usable space was assessed. Using cage measurements taken from 180 commercial houses, we found that usable space declined as the specification for cage height increased from 30.5 to 47.0 cm (12 to 18.5 in.), with this decline occurring more rapidly for A-frame than vertical cages. When cage height was set at 35.6 cm (14 in.), almost all houses had cages with usable space. When it was set at 40.6 cm (16 in.), 97.5% of houses with vertical cages and only 30% of houses with A-frame cages had cages with any usable space. Although additional investigation into the effects of cage height on hen productivity and welfare is required to establish a scientifically justified cage height recommendation, this tool will be useful for producers and engineers in determining usable space across a range of hen strain sizes and cage designs.

Day length and intensity are commonly manipulated aspects of the light environment in commercial broiler production. Both influence circadian rhythms, but it is unclear if they do this independently or synergistically. The effect of light:dark (20L:4D, 16L:8D) and intensity contrasts (1 lx:0.5 lx, 200 lx:0.5 lx) on broiler behavior and health (n=1,004, 4 replicates/treatment) was evaluated. Activity was measured using passive infrared detection, and feeding activity was measured by the amount of feed consumed/h over one 24-h period each week. Broilers were gait scored and weighed at 6 wk of age. Following euthanasia, eyes were dissected from 30 birds/treatment. Behavior and performance were analyzed using the GLM, gait score using the Kruskal-Wallis test, and eye measures using a MANOVA. The 200 lx birds were more active (P=0.03) and fed more (P=0.001) during the photophase but were less active (P=0.02) and fed less (P

The NIMH's new strategic plan, with its emphasis on the "4P's" (Prediction, Pre-emption, Personalization, and Populations) and biomarker-based medicine requires a radical shift in animal modeling methodology. In particular 4P's models will be non-determinant (i.e. disease severity will depend on secondary environmental and genetic factors); and validated by reverse-translation of animal homologues to human biomarkers. A powerful consequence of the biomarker approach is that different closely related disorders have a unique fingerprint of biomarkers. Animals can be validated as a highly specific model of a single disorder by matching this 'fingerprint'; or as a model of a symptom seen in multiple disorders by matching common biomarkers. Here we illustrate this approach with two Abnormal Repetitive Behaviors (ARBs) in mice: stereotypies and barbering (hair pulling). We developed animal versions of the neuropsychological biomarkers that distinguish human ARBs, and tested the fingerprint of the different mouse ARBs. As predicted, the two mouse ARBs were associated with different biomarkers. Both barbering and stereotypy could be discounted as models of OCD (even though they are widely used as such), due to the absence of limbic biomarkers which are characteristic of OCD and hence are necessary for a valid model. Conversely barbering matched the fingerprint of trichotillomania (i.e. selective deficits in set-shifting), suggesting it may be a highly specific model of this disorder. In contrast stereotypies were correlated only with a biomarker (deficits in response shifting) correlated with stereotypies in multiple disorders, suggesting that animal stereotypies model stereotypies in multiple disorders.

Egg production systems have become subject to heightened levels of scrutiny. Multiple factors such as disease, skeletal and foot health, pest and parasite load, behavior, stress, affective states, nutrition, and genetics influence the level of welfare hens experience. Although the need to evaluate the influence of these factors on welfare is recognized, research is still in the early stages. We compared conventional cages, furnished cages, noncage systems, and outdoor systems. Specific attributes of each system are shown to affect welfare, and systems that have similar attributes are affected similarly. For instance, environments in which hens are exposed to litter and soil, such as noncage and outdoor systems, provide a greater opportunity for disease and parasites. The more complex the environment, the more difficult it is to clean, and the larger the group size, the more easily disease and parasites are able to spread. Environments such as conventional cages, which limit movement, can lead to osteoporosis, but environments that have increased complexity, such as noncage systems, expose hens to an increased incidence of bone fractures. More space allows for hens to perform a greater repertoire of behaviors, although some deleterious behaviors such as cannibalism and piling, which results in smothering, can occur in large groups. Less is understood about the stress that each system imposes on the hen, but it appears that each system has its unique challenges. Selective breeding for desired traits such as improved bone strength and decreased feather pecking and cannibalism may help to improve welfare. It appears that no single housing system is ideal from a hen welfare perspective. Although environmental complexity increases behavioral opportunities, it also introduces difficulties in terms of disease and pest control. In addition, environmental complexity can create opportunities for the hens to express behaviors that may be detrimental to their welfare. As a result, any attempt to evaluate the sustainability of a switch to an alternative housing system requires careful consideration of the merits and shortcomings of each housing system.

Environmental stimuli present during incubation can affect the behavior and health of birds posthatch. Commercial broiler chickens are often incubated in complete darkness, receiving light only intermittently when the incubator is opened. To determine the effect of providing light during the prehatch period, we incubated Cobb broiler eggs (n = 664) under continuous light (24L:0D), no light (0L:24D), or 12 h of light (12L:12D); the light level was 550 lx. Various parameters were measured posthatch in these broilers (n = 506), which were raised in floor pens on a 12L:12D regimen. There were no incubation treatment differences in hatchability, mortality, growth, feed consumption, feed conversion ratio, gait score, overall feeding behavior activity, or general behavioral activity. However, broilers hatched from eggs incubated under 24L:0D or 12L:12D had greater feeding activity (P < 0.05) than the 0L:24D broilers during the 2 h after the lights came on. Eye dimensions did not differ between treatments, but the eyes of the 12L:12D broilers weighed less (P < 0.05) than those of the other treatments. Broilers incubated under 0L:24D had a greater level of composite physical asymmetry (1.87 +/- 0.11 mm), considered to be an indicator of developmental stress, than did 12L:12D (1.57 +/- 0.09 mm; P = 0.05) broilers; they also tended to have more composite asymmetry than 24L:0D (1.62 +/- 0.11 mm; P = 0.10) broilers. The results of this study indicate that providing light during incubation has no detrimental effect on production or health of broilers, but does have potential benefits in terms of reducing the effects of stressors associated with production and growth.

The northern fowl mite (NFM), Ornithonyssus sylviarum, is the most common ectoparasite of laying hens in North America. Infestation can cause a reduction in egg production, egg weights, and feed conversion efficiency. However, there is a lack of information on the effects of NFM on hen physiology, physical condition, and egg quality. Singly caged beak-trimmed White Leghorn hens (N = 32) were infested with mites at 25 wk of age. The condition of each hen was assessed at wk 0 (infestation) and wk 5 and 7 post-infestation to determine comb temperatures and feather, skin, and comb condition. Heterophil-lymphocyte (H/L) ratios and body weight (BW) were evaluated at wk 0 and wk 1, 3, 5, and 7 post-infestation. Egg weight, egg specific gravity, yolk color, Haugh unit (HU), and eggshell thickness were determined prior to infestation (wk -1) and at 1, 3, 5, and 7 wk post-infestation. The H/L ratio (P < 0.0001), HU (P < 0.0001), and egg specific gravity (P = 0.001) were lowest, and the egg yolk color was lightest (P = 0.087) at wk 5, the peak of infestation. At wk 5 and 7, more than 65% of the hens had red skin and more than 75% had scabs on the vent; in addition more than 84% had grey-black vent feathers. There were no effects of infestation on comb color, comb temperature, feather cover, BW, or eggshell thickness. It was concluded that infestation with NFM has negative effects on interior egg quality and hen integument. A decrease in H/L ratio was also observed at the peak of infestation. However, the effects of NFM on the immune system are unclear, and H/L ratio might not be a good stress measure in hens highly infested with NFM.

Stereotypic behavior is an important indicator of compromised welfare. Zoo elephants are documented to perform stereotypic behavior, but the factors that contribute to performance have not been systematically assessed. We collected behavioral data on 89 elephants (47 African [Loxodonta africana], 42 Asian [Elephas maximus]) at 39 North American zoos during the summer and winter. Elephants were videoed for a median of 12 daytime hours per season. A subset of 32 elephants (19 African, 13 Asian) was also observed live for a median of 10.5 nighttime hours. Percentages of visible behavior scans were calculated from five minute instantaneous samples. Stereotypic behavior was the second most commonly performed behavior (after feeding), making up 15.5% of observations during the daytime and 24.8% at nighttime. Negative binomial regression models fitted with generalized estimating equations were used to determine which social, housing, management, life history, and demographic variables were associated with daytime and nighttime stereotypic behavior rates. Species was a significant risk factor in both models, with Asian elephants at greater risk (daytime: p

This study quantified social life events hypothesized to affect the welfare of zoo African and Asian elephants, focusing on animals that were part of a large multi-disciplinary, multi-institutional elephant welfare study in North America. Age was calculated based on recorded birth dates and an age-based account of life event data for each elephant was compiled. These event histories included facility transfers, births and deaths of offspring, and births and deaths of non-offspring herd mates. Each event was evaluated as a total number of events per elephant, lifetime rate of event exposure, and age at first event exposure. These were then compared across three categories: species (African vs. Asian); sex (male vs. female); and origin (imported vs. captive-born). Mean age distributions differed (p

The Welfare Quality(®) Assessment protocol for poultry ( WQA: ) provides animal-based measures allowing welfare comparisons across farms and housing systems. It was used to compare Lohmann LSL Classic White hens housed in an enriched colony ( EC: ), aviary ( AV: ), and conventional cage system ( CC: ) on a commercial farm over 2 flock cycles. Hens (n = 100/system) were scored on a variety of measures. A baseline measurement was made at placement at 19 wk of age for 1 flock, since AV hens had been reared in an aviary pullet facility ( AVP: while EC and CC hens were reared in a conventional pullet facility ( CCP: ). Hens in all systems were then assessed at 52 and 72 wk of age. Necropsies were performed on all mortalities 1 wk before and after the WQA sampling. WQAs were analyzed using Mann-Whitney U and Kruskal-Wallis tests for prevalence and Fisher's exact tests for severity. There was an effect of rearing, with AVP having shorter claws (P = 0.01), dirtier feathers (P = 0.03), and more keel abnormalities (P

Finding ways to minimize pain and distress in research animals is a continuing goal in the laboratory animal research field. Pain and distress, however, are not synonymous, and measures that alleviate one may not affect the other. Here, the authors provide a summary of a meeting held in February 2004 that focused on distress in laboratory animals. They discuss the difficulties associated with defining 'distress,' propose methods to aid in recognizing and alleviating distressful conditions, and provide recommendations for animal research conduct and oversight that would minimize distress experienced by laboratory animals.

A presumed function of dustbathing behavior is to remove ectoparasites. Providing dustbathing substrates in furnished cages for laying hens might therefore offer an alternative to pesticide use to reduce ectoparasite populations. We investigated the effectiveness of dustbathing substrates for controlling northern fowl mites in individually caged beak-trimmed White Leghorn hens (N = 32). Each cage contained a 32 cm × 32 cm plastic tray that was either: (1) filled with 1200 g of sand (SAND); (2) empty (CONTROL); (3) covered with Astroturf (AT); or (4) covered with AT on to which 150 g of feed was delivered daily (ATF). AT and ATF are used in the dustbathing/foraging area of many newer commercial furnished cages. Hens were infested with approximately 35 mites at 25 weeks of age. Mite numbers were estimated weekly. Time spent dustbathing and dustbathing bout numbers and lengths in the tray and on the wire cage floor were determined from video recordings made for 2 consecutive days from 12:00 to 20:00 h immediately before and after infestation and at weeks 1, 3, 5, and 7 post-infestation. Data were analyzed using a repeated-measures ANOVA in SAS. Treatment did not influence the total time spent dustbathing (average across substrates: 11.3 min). However, there were treatment effects on the time spent dustbathing in the trays (F2,21 = 3.67, P = 0.043) and on wire (F2,21 = 7.68, P = 0.031). SAND and ATF hens spent more time dustbathing in the trays (11.4 and 9.1 min, respectively) than AT (2.3 min), and CONTROL and AT hens spent more time dustbathing on wire (11.6 and 4.7 min, respectively) than ATF (0.4 min). There was a treatment effect on infestation (F3,28 = 3.08, P = 0.04), with ATF having more mites (back-transformed mean = 1500) than AT (330), and with SAND (460) and CONTROL (447) intermediate. This study confirmed that the substrate type affected dustbathing behavior. SAND was a preferred dustbathing substrate but was not effective for controlling mite numbers, nor was the time spent dustbathing in any substrate or in total influenced by infestation levels. Our data also suggest that adding feed to the AT pad in furnished cages might lead to increased mite numbers in infested hens. The reason for this effect is unclear, but could be due to feed particles contributing to a change in feather structure that creates a more favorable mite habitat.

Although it has become increasingly popular to keep backyard chickens in the United States, few studies have provided information about these flocks. An online survey of backyard chicken owners was conducted, advertised through Master Gardeners' websites, social platforms, and other sites. The survey had 56 questions about flock history, husbandry, health care, and owner attitudes and demographics. Surveys received (n = 1,487) came almost equally from urban, suburban, and rural areas. Most (71%) respondents owned fewer than 10 chickens and had kept chickens for less than 5 yr (70%). Major reasons for keeping chickens were as food for home use (95%), gardening partners (63%), pets (57%), or a combination of these. Rural respondents had larger flocks (P ≤ 0.001) and were more likely to keep chickens as a source of income or for show (P ≤ 0.001) than urban and suburban respondents. Owners thought that eggs/meat from their chickens were more nutritious (86%), safer to consume (84%), and tasted better (95%) than store-bought products, and also that the health and welfare of their chickens was better (95%) than on commercial farms. The majority (59%) indicated no flock health problems in the last 12 mo. However, there was a lack of awareness about some poultry health conditions. Many knew either little or nothing about exotic Newcastle or Marek's disease, and most (61%) did not vaccinate against Marek's. Respondents wanted to learn more about various flock management topics, especially how to detect (64%) and treat (66%) health problems. The Internet was the main source of information (87%) used by backyard flock owners, followed by books/magazines (62%) and feed stores (40%). Minimizing predation was the most cited challenge (49%), followed by providing adequate feed at low cost (28%), dealing with soil management (25%), and complying with zoning regulations (23%). The evidence obtained from this survey will help to determine what information and resources are needed to maintain good biosecurity and improve the health and welfare of backyard flocks.

Two states in the United States now have legislation requiring that laying hens be provided with sufficient space to perform particular behaviors. To provide a framework for translating these performance standards into a space requirement, kinematic analysis was used to measure the amount of space needed for White Leghorn hens to stand, turn around 180°, lie down, and wing flap. Hyline W-36 hens (n = 9) were marked on the tops of their heads and the tips of both wings and 3 toes with black livestock marker. Each hen was then placed in a floor pen (91.4 × 91.4 cm) and filmed using 2 high-speed cameras. The resulting images were processed using a software program that generated 3-dimensional space use for each behavior. Because none of the hens lay down in the test pen, the 2-dimensional space required for lying was determined by superimposing a grid over videos of the hens lying down in their home cages. On average, hens required a mean area of 563 (± 8) cm2 to stand, 1,316 (± 23) cm2 to turn around, 318 (± 6) cm2 to lie down, and 1,693 (± 136) cm2 to wing flap. The mean heights used were 34.8 (± 1.3) cm for standing, 38.6 (± 2.3) cm for turning, and 49.5 (± 1.8) cm for wing flapping. However, space requirements for hens housed in multiple-hen groups in cage or noncage systems cannot be based simply on information about the space required for local movement by a single hen. It must also incorporate consideration of the tendency of hens in a flock to synchronize their behaviors. In addition, it must include not just local movement space but also the space that hens may need to use for longer-distance movements to access resources such as food, water, perches, and nest boxes.

In the United States, empirical information on the sustainability of commercial-scale egg production is lacking. The passage of state regulations specific to hen housing created urgency to better understand the effects of different housing systems on the sustainability of the egg supply, and stimulated the formation of a coalition, the Coalition for a Sustainable Egg Supply (CSES), to conduct research on this topic. The CSES is a multi-stakeholder group with 27 members, including food manufacturers, research institutions, scientists, restaurants, food service, retail food companies, egg suppliers, and nongovernmental organizations. A commercial-scale study was developed to better understand the effect of 3 housing systems (conventional cage, enriched colony, and cage-free aviary) on 5 areas related to a sustainable egg supply. These 5 sustainability areas represent effects on people, animals, and the environment: animal health and well-being, environment, food safety, worker health and safety, and food affordability. Five teams of scientists, each associated with a sustainability area, conducted an integrated field study at a commercial site in the upper Midwest through 2 flock cycles in 3 housing systems. This paper provides a brief overview of the CSES project to serve as an introduction for the papers that follow in this volume of Poultry Science.

This experiment was conducted to determine the effect of elevated plasma corticosterone (CORT) levels on meat quality characteristics. Male broilers (Arbor Acres) were either 1) fed a diet containing corticosterone (CORT) prior to processing, 2) transported by truck for 3 h before processing, or 3) processed without either of the above treatments. Six crates of birds (10 birds per crate; two crates per treatment) were stunned or killed using CO2 gas. Six birds per crate were processed and blood samples were collected during exsanguination for plasma CORT analysis. Meat samples were collected from carcasses either at 20 min or at 4 h post-mortem. At each sampling time (ST), Pectoralis superficialis samples were collected and either individually quick frozen (IQF) in liquid nitrogen or aged on ice (AOI) for 24 h prior to pH, ratio of inosine to adenosine nucleotides (R-value), cooking loss, shear value, and color analyses. The IQF Biceps femoris samples were used for pH, R-value, color, and heme pigment analysis. Mean (+/- SEM) CORT concentrations were 12.9+/-2.57, 11.7+/-1.38 and 7.9+/-0.79 ng/mL, respectively, in the CORT, transported, and control groups. There were significant treatment by ST (P < 0.05) and ST (P < 0.001) effects on the R-value of IQF P. superficialis samples. The CORT group had the highest L* value (P < 0.01) and the lowest a* value (P < 0.06). There was also a significant main effect of ST on shear values (P < 0.05) of AOI P. superficialis samples, with the means higher at 4 h than at 20 min post-mortem. The R-value of IQF B. femoris samples was markedly influenced by treatment (P < 0.001) and ST (P < 0.001). The results indicate that artificially elevating circulating CORT concentrations results in lighter meat color in broilers.

Experiments were conducted to determine 1) whether different crating durations influence stress responses and meat quality in broilers, and 2) whether holding crated broilers after transport influences corticosterone (CORT) levels and meat quality. In a preliminary experiment, male broilers (n = 50) were held in crates (10 birds per crate) for either 0, 1, 2, 3, or 4 h prior to processing. Crating duration did not affect plasma CORT level, cooking loss, shear value of breast or thigh muscles, or carcass skin discolorations. Crating duration also did not affect the color (L*, a*, b*, chroma, and hue angle) of breast meat, but did change the color of thigh meat, with samples from the 3 h crating group having the highest hue values (P0.01). Corticosterone concentrations and hue values of thigh samples were positively correlated (P0.05, r = 0.244). In Experiment 1, broilers (n = 36) were crated for either 1 or 3 h, with 9 birds per crate. Crating time did not influence plasma CORT, epinephrine, or norepinephrine concentrations, initial pH, color, or texture of breast and thigh meat samples. In Experiment 2, broilers were crated (nine birds per crate) early in the morning and transported 3 h to the processing facility by truck. Nine crates of birds were held in a dark quiet place for 4 h prior to processing (H) and the remaining nine crates were processed immediately (NH). Corticosterone levels were significantly lower (P0.01) in the H group than in the NH group. Initial pH of thigh meat of the H group was also significantly lower (P0.01), although breast meat pH was not affected by treatment. Holding had no effect on shear values, color (breast and thigh), or total heme concentration (thigh). There was a significant correlation (P0.01, r = 0.302) between CORT levels and hue values of thigh meat. These results suggest that higher preslaughter stress levels in broilers could influence the color of thigh meat, although overall meat quality was not affected under the conditions of this study.

Providing light during incubation has been shown to decrease bilateral physical asymmetry of broilers posthatch, which may indicate that early light stimulation reduces later stress susceptibility. This experiment evaluated the effects of lighting during embryogenesis on other measures of stress responsiveness in broilers. Cobb 500 eggs (n = 1,404) were incubated under 0L:24D, 1L:23D, 6L:18D, or 12L:12D; the light level was 550 lx. The broilers were then raised in floor pens under a 12L:12D lighting regimen, and various stress parameters were measured during wk 3 to 6 of age. There was an effect of incubation lighting regimen on posthatch stress responses. Following 1 h of crating, the change in corticosterone (CORT) concentration was less in the 12L:12D (-0.06 ng/mL, P0.05) treatment than all other treatments (pooled mean = 0.24 ng/mL); however, there were no treatment differences in CORT response to adrenocorticotropic hormone administration (pooled mean pre- vs. 1 h postadministration = 17.5 ng/mL, P0.05). Anti-keyhole limpet hemocyanin titers were higher in the 12L:12D birds (92,395 units/mL; P0.05) than all other treatments (pooled mean = 68,407 units/mL) on d 1 postcrating. Additionally, composite asymmetry scores were lower in the 12L:12D treatment (0.92 mm) than all other treatments (pooled mean = 1.14 mm, P0.05). These results demonstrate that providing 12 h of light per day during incubation can reduce the stress susceptibility of broilers posthatch.

Psittacines are generally considered to possess cognitive abilities comparable to those of primates. Most psittacine research has evaluated performance on standardized complex cognition tasks, but studies of basic cognitive processes are limited. We tested orange-winged Amazon parrots (Amazona amazonica) on a spatial foraging assessment, the Hamilton search task. This task is a standardized test used in human and non-human primate studies. It has multiple phases, which require trial and error learning, learning set breaking, and spatial memory. We investigated search strategies used to complete the task, cognitive flexibility, and long-term memory for the task. We also assessed the effects of individual strength of motor lateralization (foot preference) and sex on task performance. Almost all (92 %) of the parrots acquired the task. All had significant foot preferences, with 69 % preferring their left foot, and showed side preferences contralateral to their preferred limb during location selection. The parrots were able to alter their search strategies when reward contingencies changed, demonstrating cognitive flexibility. They were also able to remember the task over a 6-month period. Lateralization had a significant influence on learning set acquisition but no effect on cognitive flexibility. There were no sex differences. To our knowledge, this is the first cognitive study using this particular species and one of the few studies of cognitive abilities in any Neotropical parrot species.

Hen performance can be affected by many interacting variables related to cage design, such as floor area, height, tier arrangement, and feeder and drinker type and placement within the cage. Likewise, features of house design such as waste management and lighting can also affect hen productivity. The influence of these design aspects on hen performance has not been fully assessed. Determining the effects of numerous, interacting variables is impractical in a traditional experiment; therefore, an epidemiological approach, using variability in cage and house design among and within commercial producers, was employed to identify features that affect egg production and egg weight. A universal cage measurement system was created to calculate cage design variables. A database for recording information on cage design, resource location, waste management, environmental conditions, and hen productivity was developed. Production outcomes were assessed from placement to 60 wk of age in White Leghorns (n = 165-168 houses). Using GLM, a statistical model was identified that best described the variance in egg traits. Eggs/hen-housed increased with greater feeder space allocation (P = 0.031); taller cages (P = 0.029); rear (vs. front) drinker location in vertical cages (P = 0.026); and regular removal of manure from the house (P = 0.005). Case weight of eggs was greater in A-frame houses where manure was removed regularly instead of being left in the house (P < 0.001); with increasing cage floor slope (P = 0.001); in cages where drinkers were placed more toward the front or back of the cage as compared with the middle of the cage (P < 0.001); with more space/hen (P = 0.024); and with higher caloric intake (P < 0.001). Perhaps because of its negative correlation with egg production, case weight of eggs increased with less feeder space allocation (P = 0.004) and shorter cage heights (P < 0.001). These results reveal important effects of feeder space, floor space, cage height, drinker position, and waste management on hen productivity.

This part updates the underlying report: The welfare of chickens kept for meat production (2000, available at http://ec.europa.eu/food/fs/sc/scah/out39_en.pdf).

Social network analysis is increasingly used by behavioral ecologists and primatologists to describe the patterns and quality of interactions among individuals. We provide an overview of this methodology, with examples illustrating how it can be used to study social behavior in applied contexts. Like most kinds of social interaction analyses, social network analysis provides information about direct relationships (e.g. dominant–subordinate relationships). However, it also generates a more global model of social organization that determines how individual patterns of social interaction relate to individual and group characteristics. A particular strength of this approach is that it provides standardized mathematical methods for calculating metrics of sociality across levels of social organization, from the population and group levels to the individual level. At the group level these metrics can be used to track changes in social network structures over time, evaluate the effect of the environment on social network structure, or compare social structures across groups, populations or species. At the individual level, the metrics allow quantification of the heterogeneity of social experience within groups and identification of individuals who may play especially important roles in maintaining social stability or information flow throughout the network.

The laying of eggs outside nest boxes is a common problem in poultry production systems. Fac- tors potentially contributing to floor laying by Pekin ducks were investigated. In a 2 × 2 factorial design, 16 groups of 18-wk-old ducks (8/group) were provided ac- cess to either 2 (4 ducks/box) or 8 (1 duck/box) closed- topped or open-topped nest boxes. Egg locations were recorded daily for 16 wk. Video analyses were used to determine the time of day eggs were laid on the floor when the ducks were 18 to 22, 26, 30, and 34 wk of age. An analysis of nontoxic dye deposition in the egg yolk was conducted on wk 30, 32, and 36 to determine the contribution of each duck to floor laying. The propor- tion of floor eggs was especially high early in the laying cycle, reaching 84 and 44% of eggs laid in pens offer- ing ratios of 4 ducks/box and 1 duck/box, respective- ly, when ducks were 22 wk of age. Repeated measures ANOVA revealed that although the proportion of floor eggs decreased over time (F3,9 = 29.29, P < 0.0001), it remained greater in the groups housed with 4 ducks/ box vs. 1 duck/box (F1,11 = 24.09, P = 0.0005). The proportion of floor eggs was not affected by box design (F1,11 = 0.08, P = 0.8). Not all available nest boxes contained eggs on a given day, and the distribution of eggs within the pen was clumped. However, it was un- likely that this reflected nest box location preferences because the locations of the eggs laid within the nest boxes changed over time. Taken together, these results suggest that floor laying by Pekin ducks may be caused in part by insufficient nest box availability. However, the clumped distribution of eggs suggests that other social factors, such as conspecific attraction, may also be important.

Four handling techniques commonly used with snakes and lizards in zoological park reptile collections were evaluated with respect to animal well-being. Adult male blue-tongued skinks (n=3) and ball pythons (n=4) were either handled gently, restrained manually, or container restrained for 10 min. The animals were then released into their enclosures for 15 min and blood sampled. At each sampling period, one animal served as an unhandled control. Plasma corticosterone (CS) levels, pre- and post-treatment locomotor and consummatory activities, and heterophil/lymphocyte ratios were determined. None of the parameters evaluated differed significantly among treatments with the exception of CS levels in container-restrained pythons (56.2±6.7 ng ml−1), which were higher (P

The US egg industry is being pressured from many directions to change its production practices, particularly to address concerns about hen welfare in conventional cage systems. Responding to similar pressures, in 1999, the European Union banned conventional laying cages starting in 2012. This now impending European ban has led to the development of several alternative housing systems. These include noncage systems like aviaries and modified (enriched or furnished) cages that include perches, areas in which the hens can forage and dustbathe, and nests. Understanding the European experience is valuable as the United States considers the future direction of the egg industry. In the United States, the proportion of eggs produced in alternative systems is small (less than 5% of output) but growing, in part due to market and political incentives for systems that provide hens with more behavioral freedom than conventional cages. Animal welfare, however, is only one element of a sustainable production system. Other elements include those related to public values, the environment, economics, worker health, and food safety and quality. Eggs are a primary source of animal protein globally, and the United States is the third largest producer of eggs in the world, behind China and the European Union. The national table egg flock comprises about 280 million hens housed in all regions but with approximately 60% of eggs produced in the 10 leading states. Adopting new housing systems will have substantial effects on costs and other aspects of egg production on both a regional and national scale, with some positive effects but also potential negative effects that need to be carefully considered. This paper discusses the US egg industry in the context of legislation and standards related to hen housing systems. It also addresses initiatives by retailers, nongovernmental organizations, and private certification organizations to shape production practices in the egg industry as well as how those initiatives might affect various aspects of the sustainability of egg production.

Beginning January 1, 2015, conventional cage housing for egg-laying hens is scheduled to be prohibited in California. We consider the economic implications of the new hen housing regulations on the California shell egg industry. Our data show that egg production is more costly using noncage systems than conventional cages. The main result of the new regulations will be a drastic reduction in the number of eggs produced in California, a large increase in egg shipments from out of state, little if any change in hen housing for eggs consumed in California, and little change in egg prices in California.

Insufficient feeder space for laying hens could increase competition at the feed trough, leading to disrupted feeding, inadequate nutrient intake, stress, and reduced productivity. The effects of feeder space allocation (FSA) on physiology and productivity were evaluated in beak-trimmed Hy-Line W-36 hens (n=480). They were obtained at 16.5 wk of age and housed on 4 tiers of shallow conventional cages. Five pullets/cage were housed at a stocking density of 434 cm2/hen and a feeder space of 12.2 cm/hen. After 1.5 wk of acclimation, baseline measurements were taken for feed utilization, bone mineralization, and heterophil:lymphocyte ratios. At 20 wk of age, pullets were given 5.8, 7.1, 8.4, 9.7, 10.9, or 12.2 cm of feeder space/bird (16 cages/treatment). Physiological and production measures were calculated monthly or twice a month for 12 mo. The heart, spleen, and right adrenal gland were collected from each hen at the end of the study. Data were analyzed using a repeated measures GLM incorporating cage, tier, FSA, and hen age. There were no effects of FSA on total egg production, bone mineral density, bone mineral content, heterophil:lymphocyte ratios, or organ weights. Hens with reduced FSA utilized more feed (P0.001), had poorer feed conversion (P0.001), and laid eggs with slightly thicker and heavier shells (P0.001). There were effects of FSA on total egg weight (P0.001) and hen-day egg production (P0.001), but they were of low magnitude and not linear (P0.05). Because BW was similar among FSA treatments, the results suggest that reduced feeder space did not limit feed intake. In addition, reduced FSA did not lower bone mineralization or cause physiological stress in W-36 hens housed in shallow cages, suggesting that it did not impair hen welfare. However, it did result in poorer feed efficiency, possibly related to greater feed wastage, predictive of an adverse economic effect from reducing feeder space.

Insufficient feeder space for laying hens could increase competition at the feed trough, resulting in exclusion of low-ranking hens from the feeder. To test this hypothesis, the effects of feeder space allocation (FSA) on feeding behavior, aggression, feather scores, BW, and mortality were evaluated in a common commercial strain of egg-laying chickens. Beak-trimmed Hy-Line W-36 hens (n = 480) were obtained as pullets at 16.5 wk of age and housed in conventional cages on 4 tiers. Five pullets/cage were housed at a stocking density of 434 cm(2)/pullet and an FSA of 12.2 cm/pullet. After 1.5 wk of acclimation, baseline measurements were taken for 2 wk and then pullets were given either 5.8, 7.1, 8.4, 9.7, 10.9, or 12.2 cm of feeder space/hen (16 cages/treatment). Feeding behavior was evaluated in each cage over a 24-h period each month. For each hen, percentage of time spent feeding and synchrony (mean number of additional hens feeding at the same time) were determined and scores were averaged for each cage. For each cage, feeder switching (number of observations in which hens changed from feeding to not feeding) and feeder sharing (probability that feeder access was equally distributed among all hens) were calculated. At monthly intervals, individual hens were weighed and their feathers scored using a 5-point scale on 8 body regions. Data were analyzed using a repeated measures GLM incorporating cage, tier, FSA, and age of the hen. Hens with reduced feeder space spent less time feeding (P0.001), synchronized their feeding bouts to a lesser extent (P0.001), made fewer switches at the feeder (P0.001), and shared the feeder less (P0.001). However, feather scores, BW, and BW uniformity were not affected by FSA. There was almost no aggressive behavior and little mortality. These results demonstrate that Hy-Line W-36 hens did not respond to reduced feeder space by aggressively excluding cage-mates from the feeder but instead desynchronized their feeding behavior.

The corticosterone response of immature broiler breeder males to feed restriction and the administration of increased levels of dietary Trp was investigated. Corticosterone levels were significantly (P less than .01) higher in birds placed on a skip-a-day (SD) feed restriction regimen from 4 to 15 wk of age than in birds fed an ad libitum intake. Elevated levels in SD birds persisted for the duration of the study. Levels were also higher in SD birds on those days on which feed was withheld (FEED-OFF) than on those days on which feed was delivered (FEED-ON). The SD males consuming a diet containing 1.5% Trp showed a change in the pattern of hormone secretion as compared with SD control birds (.19% Trp), with corticosterone levels increasing on the FEED-ON days and decreasing on the FEED-OFF days. It is concluded that SD feed restriction causes a persistent elevation of plasma corticosterone in broiler breeders. The secretory pattern of corticosterone can be modulated by increasing the Trp content of the diet, possibly as a result of reciprocal interactions between the serotonergic system and the hypothalamic-pituitary-adrenal axis.

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Broilers are typically raised commercially in dim lighting. It has been suggested that providing brighter light intensity could improve health and provide opportunities for more normal behavioral rhythms. We examined the effects of 3 photophase light intensities (5, 50, and 200 lx) on activity patterns, immune function, and eye and leg condition of broilers (n = 753; 6 replicate pens/treatment). Broilers were reared with one of these intensities from 1 to 6 wk of age; photoperiod consisted of 16L:8D with 1 lx intensity during the scotophase. Broilers reared with 5 lx were less active (P = 0.023) during the day than 50 or 200 lx and showed less (P < 0.0001) change in activity between day and night than 50 or 200 lx. There was no difference between treatments for final BW (2.30 +/- 0.02 kg) or for most immune parameters (IgG primary and secondary responses to keyhole limpet hemocyanin, B and T lymphocyte proliferation, plasma lysozyme, haptoglobin, NO, whole blood killing of Escherichia coli and Staphylococcus aureus), but there was a trend (P = 0.072) for a greater IgM response in 50 lx (6.21 titer) than 5 lx (5.78 titer), with 200 lx (5.92 titer) intermediate. There was no effect of light intensity on back-to-front (1.13 +/- 0.01 cm) or side-to-side (1.48 +/- 0.01 cm) diameter of the eyes or on corneal radii (0.82 +/- 0.01 cm), but 5 lx (2.33 +/- 0.07 g) had heavier eyes (P = 0.002) than 50 lx (2.09 +/- 0.04 g) or 200 lx (2.11 +/- 0.04 g). There were no differences in gait score, although 200 lx broilers had more hock and footpad bruising (P = 0.038) but fewer erosions (P = 0.006) than 5 or 50 lx. Increased daylight intensity had little effect on broiler health but resulted in more pronounced behavioral rhythms.

Two experiments were conducted to assess the effect of genotype, production system, and nutrition on performance and livability of meat chickens for niche markets. Slow-growing (SG) and fast-growing genotypes (FG) were raised for 91 and 63 d, respectively, in experiment 1 (females) or 84 and 56 d, respectively, in experiment 2 (males). In each trial, SG were placed before FG to achieve a similar BW at processing. In experiment 1, each genotype was assigned to 8 pens of 20 birds each, with 4 pens within each genotype raised indoors in a conventional research facility or in a small facility with outdoor access. All birds were fed a low-nutrient diet. In experiment 2, genotype assignment to pens was as in experiment 1; however, 4 pens within each genotype were fed a low-nutrient diet or a conventional diet, and birds were raised indoors. Birds were gait-scored and commercially processed; legs were examined for tibial dyschon-droplasia lesions and scanned for bone mineral density. In experiment 1, FG gained more weight than SG (P0.05) even though they were placed later. Outdoor access increased feed intake, and feed efficiency was poorer (P0.05). Fast-growing genotypes had higher breast meat yield, whereas SG had higher wing and leg yields (P0.05). In experiment 2, the low-nutrient diet reduced (P0.05) gain of the SG; FG increased feed intake of the low-nutrient diet such that their gain was unaffected (P0.05). For FG, the low-nutrient diet resulted in a poorer (P0.05) feed efficiency. Although weight gain of the FG was maintained on the low-nutrient diet, breast yield was reduced (P0.05). Genotype affected bone health in both experiments, with SG having better gait scores and less tibial dyschondroplasia (P0.05). Outdoor access and the low-nutrient diet also resulted in better gait score (P0.05). These data indicate differences among genotypes and provide information about the efficiency and potential for alternative poultry systems.

Pekin ducks are often bill-trimmed to prevent feather pecking and cannibalism, but this practice has been criticized because of the resulting potential for acute and chronic pain. The goal of this experiment was to compare 2 different bill-trimming methods, hot blade trimming with cautery (TRIM) and cautery only (tip-searing; SEAR), on the behavior, bill morphology, and weight gain of Pekin ducks. Ducklings (n = 192, 96 per sex) were trimmed at the hatchery and assigned to 12 floor pens (3.66 x0.91 m) by treatment. Behavior was evaluated by scan sampling, and plumage condition was scored using a 0 to 3 scoring system. Thirty-six ducks were randomly euthanized at 3 and 6 wk of age, and their bills were collected for examination. Following fixation and decalcification, the bills were embedded in paraffin wax and sectioned longitudinally. Alternate sections were stained with hematoxylin and eosin and Masson's trichrome for the connective tissues, and with Bielschowsky's silver impregnation, Bodian's staining, and Holmes' staining for the nerve fibers. Trimmed ducks engaged in fewer bill-related behaviors and rested more than untrimmed ducks (NOTRIM) during the first 2 wk posttrim. Ducks in the SEAR and NOTRIM groups showed similar patterns of weight gain, but those in the TRIM group had a lower rate of gain than ducks in the SEAR group during the first week posttrim and had a lower rate of gain than those in the NOTRIM group for 2 wk posttrim. Feather scores of ducks in the NOTRIM group were significantly worse than those in the TRIM or SEAR group by 18 d, and scores continued to deteriorate at a greater rate than those of trimmed ducks throughout the study. Both trimming methods caused connective tissue proliferation in the bill stumps, but the TRIM method caused thicker scar tissue than the SEAR method. No neuromas were found with either trimming method, but there were more nerve fibers in bill stumps of the SEAR ducks than the TRIM ducks. These results suggest that acute pain is associated with both trimming methods, but that SEAR may be a preferable method, causing less check in weight gain and fewer bill morphological changes while still being effective in minimizing feather pecking damage.