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Selection for rapid growth has produced heavier, more efficient broiler chickens, but has also introduced health and welfare issues, which may cause or be caused by inactivity. Rapid growth may also limit the performance of motivated behaviors, whereas the provision of enrichment may increase these behaviors and general activity. This study aimed to evaluate the inactivity, behavior, and enrichment use of 2 fast- (CONV) and 12 slower-growing broiler strains [categorized as fastest (FAST), moderate (MOD) and slowest slow (SLOW), based on their growth rates]. To evaluate inactivity, one male and one female from 153 pens were outfitted with omni-directional accelerometers from day 21 until processing (14–24 birds/strain from 8-12 pens/strain). Additionally, to supplement inactivity data, five-minute continuous behavioral observations of four focal birds per pen (2 males, 2 females) were conducted on days 26, 42, and 56 (72–148 observations of 8–12 pens/strain) to quantify the duration and frequency of various behaviors; at the same time, 5–11 instantaneous scan samples were also performed for pen-based enrichment use. Inactivity peaked at 78-80% of the day for all strains; however, those with slower growth rates reached these levels at older ages. Compared to slower-growing strains at the same age, faster-growing strains were more inactive, spent more time sitting and feeding, spent less time standing and walking, and used enrichments less; these differences mostly occurred at younger ages. Generally, at the same age, strains with similar growth rates (within the same category) behaved similarly, with only a few exceptions. Results suggest that not all strains identified as ‘slow-growing’ broilers behave differently from fast-growing broilers, nor do they all behave similarly to each other. As such, results suggest that improved broiler welfare, particularly with respect to reduced inactivity, the performance of a wider range of normal, motivated behaviors, and/or increased enrichment use, is related to the broiler strain’s specific growth rate.

To meet the growing consumer demand for chicken meat, the poultry industry has selected broiler chickens for increasing efficiency and breast yield. While this high productivity means affordable and consistent product, it has come at a cost to broiler welfare. There has been increasing advocacy and consumer pressure on primary breeders, producers, processors, and retailers to improve the welfare of the billions of chickens processed annually. Several small-scale studies have reported better welfare outcomes for slower-growing strains compared to fast-growing, conventional strains. However, these studies often housed birds with range access or used strains with vastly different growth rates. Additionally, there may be traits other than growth, such as body conformation, that influence welfare. As the global poultry industries consider the implications of using slower growing strains, there was a need for a comprehensive, multidisciplinary examination of broiler chickens with a wide range of genotypes differing in growth rate and other phenotypic traits. Tomeet this need, our team designed a study to benchmark data on conventional and slower-growing strains of broiler chickens reared in standardized laboratory conditions. Over a 2-year period, we studied 7,528 broilers from 16 different genetic strains. In this paper, we compare the growth, efficiency, and mortality of broilers to one of two target weights (TW): 2.1 kg (TW1) and 3.2 kg (TW2). We categorized strains by their growth rate to TW2 as conventional (CONV), fastest-slow strains (FAST), moderate-slow strains (MOD), and slowest-slow strains (SLOW). When incubated, hatched, housed, managed, and fed the same, the categories of strains differed in body weights, growth rates, feed intake, and feed efficiency. At 48 d of age, strains in the CONV category were 835 to 1,264 g heavier than strains in the other categories. By TW2, differences in body weights and feed intake resulted in a 22 to 43-point difference in feed conversion ratios. Categories of strains did not differ in their overall mortality rates. Global Animal Partnership, Canada First Research Excellence Fund, Ontario Agri-Food Innovation Alliance, and Protekta

The accompanying dataset for this article is available at: Dawson, Lauren C.; Widowski, Tina M.; Zhenzhen, Liu; Edwards, A. Michelle; Torrey, Stephanie, 2022, "Replication data for: In pursuit of a better broiler: a comparison of the inactivity, behavior, and enrichment use of fast- and slower growing broiler chickens", https://doi.org/10.5683/SP3/JQ5JHU, Borealis. Selection for rapid growth has produced heavier, more efficient broiler chickens, but has also introduced health and welfare issues, which may cause or be caused by inactivity. Rapid growth may also limit the performance of motivated behaviors, whereas the provision of enrichment may increase these behaviors and general activity. This study aimed to evaluate the inactivity, behavior patterns, and enrichment use of 2 fast- (CONV) and 12 slower-growing broiler strains (categorized as fastest [FAST], moderate [MOD], and slowest slow [SLOW]), based on their growth rates; 4 strains/category]. To evaluate inactivity, one male and one female from 153 pens were outfitted with omnidirectional accelerometers from d 21 until processing (14 −24 birds/strain from 8 to 12 pens/strain). Additionally, to supplement inactivity data, 5-min continuous behavioral observations of four focal birds per pen (2 males, 2 females) were conducted on days 26, 42, and 56 (72−148 observations of 8−12 pens/strain) to quantify the duration and frequency of various behaviors; at the same time, 5 to 11 instantaneous scan samples were also performed for pen-based enrichment use. Inactivity peaked at 78 to 80% of the day for all strains; however, those with slower growth rates reached these levels at older ages. Compared to slower growing strains at the same age, faster growing strains were more inactive, spent more time sitting and feeding, spent less time standing and walking, and used enrichments less; these differences mostly occurred at younger ages. Generally, at the same age, strains with similar growth rates (within the same category) behaved similarly, with only a few exceptions. Results suggest that not all strains identified as “slow-growing” broilers behave differently from fast-growing broilers, nor do they all behave similarly to each other. As such, results suggest that improved broiler welfare, particularly with respect to reduced inactivity, the performance of a wider range of normal, motivated behaviors, and/or increased enrichment use, is related to the broiler strain’s specific growth rate. Global Animal Partnership, Canada Research Excellence Fund, Ontario Agri-Food Innovation Alliance, and Protekta

This study investigated whether simple, cheap enrichments – ‘get-away bunks' (a wire mesh semi-cylinder attached to the cage ceiling) and small manipulable objects (balls and suspended chewing items) – could improve welfare and productivity in nursing mink dams ( Neovison vison ) in commercial farm conditions in southern Ontario (Canada). Experiment 1 replicated a study conducted the previous whelping season on the same farm. It evaluated whether providing bunks to multiparous dams ( n =164) could decrease their morbidity and mortality or boost kit weaning weight, and assessed dams' overnight use of these structures to compare day and night utilization. Overnight bunk-use proved to be no different from daytime use, and night- and day-use co-varied; bunk use recorded in daylight is thus a good proxy for overall use. Bunk use did not, however, influence kit weights at weaning, nor reduce dam deaths from nursing sickness (replicating the previous year's findings), nor significantly improve subjectively scored teat health (unlike the previous year's findings). Experiment 2 reassessed bunk effects using larger sample sizes, and investigated their interaction with enrichment objects. Focusing on primiparous dams ( n =318), it evaluated whether providing balls and items to chew, along with bunks in a cross-factored design, could decrease stereotypic behaviour, glucocorticoid output (assessed via faecal cortisol metabolites: FCM), kit losses, and, again dam mortality. Objects were provided c. 10 months earlier (since the previous July) for approximately 60% of the object-enriched dams, and c. 5 months earlier (since January) for the remaining 40%. Analyses showed that effects of bunks and enrichment-objects did not significantly interact for any variable. Bunks significantly reduced kit mortality: kit losses/litter were reduced by c. 0.3 infants, resulting in negligible levels of mortality, and bunks tended to reduce dam stereotypy levels by about half (from approximately 12.5% to 6% of time spent active). However, bunks had no significant effects on FCM or dam mortality rates. Bunk-use also significantly co-varied with litter size, being greatest in dams with bigger litters. Enrichment objects tended to increase weaning litter size, an effect caused by dams provided with these objects for 5 months weaning 0.9 more kits per litter than females without these items. However, this type of enrichment again had no significant effects on FCM or dam mortality. Instead, which farm animals lived on appeared to be the major determinant of FCM and dam mortality: both significantly varied between farms, with one farm showing notably higher levels of both. Also, even controlling for farm, females who died tended to have had elevated glucocorticoids when sampled 2–3 weeks prior to death. In conclusion, bunks and manipulable enrichment objects seem ineffective against nursing sickness, but had independent, additive effects on the productivity of young adult females, possibly acting by improving primiparous dams' welfare.

Farmed mink infants (Neovison vison) remain with their mothers beyond natural weaning age. This benefits their welfare, but can stress their mothers and contribute to illness (e.g. ‘nursing sickness’). European studies have explored augmenting cages with structures allowing mothers to get away from their infants (‘kits’); these show that if provided with high, shelf-like structures permitting rest away from kits, dams utilise them. Here, we assessed the benefits of providing an elevated ‘getaway bunk’ – a wire-mesh half-cylinder attached to the cage ceiling – to 80 Black dams on an Ontario farm. Controls comprised nursing females without bunks (n = 80), and barren females given bunks (n = 40). Behaviour was observed daily over kit ages 23–42 days. Mothers were removed from litters at 42 days (typical for North American farms), at which time health and production parameters were recorded. Mothers used bunks approximately half as much as barren dams, but their bunk-use increased as kits aged, up to c. 7% scans (c. 30 min per observation day). Seasonal changes in temperature did not explain this pattern. Bunks increased maternal rest (from 78.9 to 82.3% of scans; c. 16 min per observation day), and increased the time spent with teats inaccessible to kits by a similar amount. Dams with bunks showed approximately one third less stereotypy (3.7% scans, compared to 5.4% in bunkless controls): a reduction most evident when kits were aged 30–42 days, when infants transition from milk to water and solid food; and, although apparently not protected from nursing sickness, at the end of lactation they were less likely to have swollen, red and/or crusty teats (which thermal imaging also showed were significantly hotter), suggesting less mastitis. Such benefits seemed particularly strong in multiparous dams: effects of bunks on teat health and stereotypy as a proportion of activity (not scans) were significant in older dams but not first-time mothers when analysed separately. Kits’ suckling opportunities and time spent nursing were not significantly reduced by the bunks, however; nor did bunks compromise kit survivorship or weights at 42 days. Elevated bunks can thus enhance mink mothers’ welfare during the nursing period, seemingly without serious drawbacks for their kits. Unexpectedly, however, all study dams had very high mortality (>20%; more than triple that of non-experimental animals on the farm), suggesting that repeated live observation, or being housed close to barren dams, may elevate risks of nursing sickness.

A half-cylinder bunk of wire-mesh was attached to the cage ceiling of 80 dams with litters. Each bunk was 35 cm long, 16.5 cm wide and 10 cm deep, along an adult female to rest in it easily; and placement in the cage was high enough that no kits could climb on or in the bunks before the dam was removed when they were 6 weeks of age (typical weaning age in North America). 80 dams with litters acted as bunk-less controls. Behavioural data were collected daily between kit ages 21 days and weaning (42 days). Kits were weighed at weaning, and post-natal mortalities recorded from their cage records. After weaning, the teats of all dams were inspected for signs of damage or infection. Dams with bunks used them regularly. Consequently, bunk-supplemented dams rested away from their kits more than did nursing dams without bunks. However, compared to bunk-less nursing dams, nursing dams with bunks spent no less time resting with their teats accessible to their kits, and also no less time nursing (a behaviour that was observed in both nest-box and cage). Their time resting away from their kits thus represented enhanced levels of inactivity: compared to standard-housed dams, they spent about 10% more observations resting/sleeping rather than being active. Furthermore, the activity of bunk-supplemented dams also differed qualitatively: when active, bunk-supplemented dams were less likely to be stereotypic. Pacing and head-twirling was thus significantly reduced in bunk dams, both in terms of the proportion of observations devoted to this behaviour, and the proportion of their active time. Furthermore, bunk dams had improved teat health: at weaning, a significantly smaller proportion of enriched nursing females had nipples that were scored as inflamed or crusted with secretions suggestive of mastitis. Despite their mothers’ enhanced abilities to rest away from them, the kits of females with bunks did not seem to be adversely affected: along with nursing and teat availability apparently being adversely affected by the provision of bunks, kit growth rates and kit mortality rates were not significantly different between the two groups (although future research should supplement these data with variables better able to detect stress and frustration in kits). Overall, elevated resting bunks enhanced the health and welfare of dams, with no apparent major ill effects to their kits.

Subjects were 2,400 kits from 600 families, on 3 commercial farms in Ontario, pair-housed from July-December. 75% were Blacks, 25% Demis. Two male-female pairs were used per family: one was provided with stimuli for interaction; the other housed in standard conditions. The supplemented cages received a golf ball, plastic wiffle ball, and hanging device to tug /chew (hose or plastic chain) (costing under $1.50 a cage). Behaviour, temperament, mortality rates and pelt quality were assessed. Supplemented kits were found to play more than their non-enriched siblings. Social play (defined as ‘rough and tumble’ interactions without screaming or hard biting) was unaffected, but enhanced object and locomotor play led to significantly higher overall levels in supplemented juveniles. There was no evidence that the added objects increased aggression. The added objects also had no effects on mortality. In stick tests in December, supplemented mink were significantly less likely to be fearful than their standard-housed siblings. When scored for reactions to the live-grading of their fur in November, supplemented mink were significantly less likely to scream than their standard-housed siblings. Across Blacks, the added objects did not seem to affect fur quality, but in Demis, supplemented mink were significantly likely to receive better live-grades than their standard-housed siblings. For pelted subjects, tails of dead animals were inspected for signs of tail-chewing/clipping. Typically 1 cm or less of the tailtip was affected. However, 20 mink across all three farms showed damage to 2 cm or more the tail, and 14 of these were standard-housed rather than supplemented: a trend to significance. Furthermore, pooling all instances of tail-chewing/-biting together, 7.9% supplemented mink had sucked/bitten tails, compared to 11.5 standard-housed: a significant effect. The pelts of all experimental mink were bar-coded for auction, and prices will be obtained in summer 2012. Data during mating showed that supplemented males were more effective maters than standard mink (e.g. showing longer copulations). Subjects selected for breeding have also been evaluated for stereotypic behaviour and faecal cortisol metabolite output, and for whelping success: data still to be analysed. Overall, these findings to date show that simple, long-term, cheap additions to standard cages can act as effective environmental enrichments for farmed mink.