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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

In response to a growing number of permissive urban animal agriculture ordinances across the nation, this research reviews the spatial and temporal attributes of urban poultry ordinances across 100 municipalities in Colorado. More poultry ordinances have been passed or modified in Colorado in the last 5 years than in the previous hundred. Comparing regulations to commercial operations and animal shelter surrenders, we find that permissive ordinances cluster near major urban areas even where they are in close proximity to large commercial operations. Most ordinances inadequately address both human and animal health and welfare concerns. Provisions governing animal slaughter and routine veterinary care are rare, presenting a concern for monitoring and intervening in public health crises. In addition, shelters anticipate higher poultry intakes, particularly as unwanted birds are turned loose to become strays.

Stereotypic behaviors (SB) are common in zoo-housed elephants, and these behaviors can be performed at high rates. Elephants perform different SB forms ( e.g., weaving, pacing), but no published studies have evaluated the factors contributing to the development or performance of these different forms. Instead, as with most SB studies across species, elephant studies have relied on analyses that aggregate all SB forms, which limits the development and testing of form-specific hypotheses or abatement practices. Our objectives were to characterize the SB forms of North American zoo elephants and use multivariable epidemiological models to test form-specific hypotheses. We videotaped 77 elephants (African: N = 5 males, 31 females; Asian N = 8 males, 33 females) at 39 zoos who performed SBs and used a novel classification scheme and 5-min instantaneous samples to characterize their SB forms. Locomotor and whole-body SBs were the most common, but most elephants who performed locomotor SBs also performed whole-body SBs. Thus, we characterized each elephant according to whether it included locomotion in its SB repertoire [Locomotor Presence (LP)] or only whole-body movements. We used binomial regression models fitted with generalized estimating equations to test hypotheses about which of 26 social, housing, management, life history, and demographic variables were most associated with LP. The odds of LP increased by 26% for every 10% increase in time housed separately (odds ratio = 1.026, p = 0.04), 96.2% for every additional social group with which an elephant had contact (odds ratio = 1.962, p = 0.01), and 46% for every 10% increase in time housed indoors (odds ratio = 1.046, p = 0.01). Age was non-significantly confounded with all three variables. We hypothesize that the social variables in our models increase LP risk because they are associated with uncontrollable social group changes, anticipation of potentially rewarding social experiences, or the frustration of social behaviors. The housing variable included in our model likely increases LP risk because indoor spaces are less complex, resulting in the channeling of walking or social avoidance behaviors into more simplistic movements. Overall, our results suggest that elephant managers may best be able to prevent locomotor SB by enhancing their elephants’ social environment and the spatial complexity of their enclosures. Future research should focus on determining whether addressing the risk factors for LP results in less frequent performance and identifying other temporally proximate eliciting factors.

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.

Animal welfare science is a relatively new field, but has grown rapidly to encompass different disciplines. The large body of published research on farm animal welfare addresses topics ranging from basic biological principles of welfare assessment to applications for evaluating and improving housing, husbandry, transport, and slaughter. This research has influenced legislation and standards setting, but concerns have been raised about its applicability in commercial settings. Most animal welfare research has been conducted in small-scale experimental settings, which are often very different from the “real world” of commercial animal production in terms of scale, complexity, automation, and variability. In this paper, I provide some examples of how science can be conducted in the “real world” to benefit both researchers and farmers, focusing on commercial-scale experimental and epidemiological research. I also discuss emerging technologies that can be used to automate the assessment of animal behavior on farms, which will allow more behavioral variables to be included in these experiments.

Commercial poultry production has changed since the 1950s. Genetic selection has resulted in two different types of commercial poultry, meat and egg-laying birds. Production systems for meat birds (chickens, turkeys, and ducks) are similar in their configuration and management, although there are some differences due to the species being grown and the desired days to market. In contrast, the table-egg industry is changing rapidly due to animal welfare concerns, particularly in developing countries, and egg-laying hens are now produced in a multitude of systems requiring different types of management expertise. We provide an overview of the commercial production systems commonly used for rearing meat birds and egg-laying hens. We also identify some of the major welfare challenges related to health and behavior within current systems, and discuss emerging consumer preferences that will shape poultry production systems, and their associated welfare concerns, in the near future.

The strategies that animals use to obtain valuable resources are affected by resource quality and availability (e.g. spatial distribution), population dynamics (e.g. competitor-to-resource ratio) and individual characteristics (e.g. competitive ability). Theoretical papers and field observations suggest that aggressive resource competition, particularly by individuals with high competitive ability, increases as the competitor-to-resource ratio increases. On the other hand, individuals with low competitive ability should adopt a scramble competitive strategy, for example by expanding their home range or utilizing resources at suboptimal times. We tested these theoretical predictions in male house mice, Mus musculus domesticus, by experimentally manipulating the distribution of a desirable resource, a running wheel. Four male mice were exposed to three treatments (zero, one or four running wheels present) using a repeated measures design. We found that aggression increased as the competitor-to-resource ratio increased. In addition, mice with high competitive ability had species-typical nocturnally biased activity and running wheel use patterns, while mice with low competitive ability had more diurnally biased activity and running wheel use patterns. Our results show that aggression encourages less competitive mice to adopt a scramble competitive strategy through temporal partitioning and provides empirical evidence for the predictions of resource defence theory.

Light stimulation during incubation can affect the behavior, health, and performance of poultry posthatch. However, there has been relatively little work systematically assessing the pattern of light stimulation needed to produce these effects or the mechanism underlying them. We conducted 2 experiments to assess the effects of duration and onset of light exposure during incubation on Cobb 500 broiler chickens. In the first, eggs (n = 1,404) were incubated under photoperiods of either 0 h of light and 24 h of darkness (0 L:24 D), 1 h of light and 23 h of darkness (1 L:23 D), 6 h of light and 18 h of darkness (6L:18D), or 12 h of light and 12 h of darkness (12L:12D). In the second, eggs (n = 1,008) were incubated in either complete darkness or under 12L:12D, which was applied either for the entire incubation period or with light onset beginning at either 7 or 14 d of incubation. Broilers were then housed in floor pens under a 12L:12D cycle posthatch. Measurements included performance outcomes, plasma melatonin, general behavioral activity assessed using passive infrared detection, and feeding activity assessed using automated continuous monitoring of feed intake at wk 5 of age. There were no treatment differences in hatchability, mortality, growth, feed consumption, feed conversion ratio, overall feeding behavior activity, or general behavioral activity over a 24-h period in either experiment. However, broilers incubated under 12L:12D fed more (P < 0.05) than the 0 L:24 D broilers during the first 3 h after the lights came on in Exp. 1 and during the first hour after the lights came on in Exp. 2. In Exp. 1, general activity levels measured using passive infrared detection at night also differed (P = 0.05), with 0 L:24 D more active than 12L:12D. There was a treatment difference between the 0 L:12 D and 12 L:12 D in their plasma melatonin rhythms during d 19 of incubation, but this difference had disappeared when broilers were sampled at wk 5 posthatch. The results of this study indicate that providing 12 h of light during incubation can have a long-lasting effect on the diurnal rhythms of behavior, although the mechanism underlying this does not appear to be related to a persistent change in melatonin rhythm.

The prevalence of stable behavioural differences between individuals of a species (i.e. personality) is puzzling because it indicates that there are limits on animals’ behavioural plasticity and, therefore, optimality of behaviour. Personality may result from individual state characteristics (e.g. morphology or physiology). In turn, these characteristics can lead to differential fitness outcomes for individuals. Cognitive processing of environmental information may be such a characteristic. We developed a subjective personality assessment for Amazona amazonica. We then assessed whether personality predicted a cognitive state difference in attention bias, as measured by the proportion of balks and errors when performing a spatial foraging task in the presence of a passive human observer. Attention biases occur either because individuals attend more quickly to certain environmental stimuli, or because they cannot disengage their attention from such stimuli. Two factors, ‘neuroticism’ and ‘extraversion’, accounted for 66% of the total variance in personality. There was individual variation between parrots’ scores on both personality factors and both factors were temporally consistent over 1 year. There was a significant correlation between neuroticism and attention bias. Evolutionarily, attention biases are selected for because the fitness cost of failing to attend to potential threats is much greater than the cost of expending energy attending to benign stimuli. Therefore, cognitive biases such as attention bias are logical candidate cognitive states driving stable personality differences. Our findings show that differences in personality in A. amazonica are correlated with attention bias, a biologically relevant difference in cognition.

Although environmental conditions during incubation can affect poultry welfare, one factor often overlooked in the commercial incubation of eggs is light. Light stimulation during embryonic development is now known to affect the physiology and behavior of broiler (meat) chickens post-hatch, but little is known about the pattern of exposure needed to produce these effects. We determined how often naturally incubated eggs were exposed to light by giving 10 broody Junglefowl × New Hampshire Red hens a nestbox containing five fertile eggs and a light sensitive data logger which recorded nest attendance by determining whether light was reaching the eggs. On average hens stayed on the nest without leaving for 14.3 of the days of the 21-day incubation cycle, although they did leave periodically, particularly during the last week. Utilizing this information, we then investigated how the timing of light exposure during incubation affected fear and stress responsiveness post-hatch in broiler chickens. Eggs were either not exposed to light (0DL), or exposed to light throughout incubation (21DL) or during only either the last 2 weeks (14DL) or the last week (7DL) of incubation. Lighting pattern had a significant effect on all parameters measured, with the most consistent differences found between 0DL and 21DL. For the fear measures, the 0DL birds had a longer latency to emerge during an emergence test (62.7 versus 37.2 s), a longer latency to right during a tonic immobility test (223.8 versus 107.2 s), wing-flapped more intensely during an inversion test (7.03 versus 6.4 flaps/s), and vocalized more during an isolation test (172.7 versus 127.1/3 min) than the 21DL. For the stress measures, 0DL had a lower IgG titer (52,683 versus 97,375 units) and greater corticosterone response (1.18 versus 0.55 ng/mL) to the crating stressor than 21DL, and showed more composite asymmetry (1.96 versus 1.49 mm). The 14DL and 7DL groups were generally intermediate. Unlike dark-incubated chicks, all light-stimulated groups showed lateralization of escape direction during the emergence test, suggesting that light-induced cerebral laterality could play a role in the observed effects. However, the direction of lateralization differed depending upon timing of exposure. These results confirm the importance of light stimulation during incubation on the later behavior and physiology of broiler chickens, but also indicate that providing light only during the last week of incubation, which would coincide with the maximum light stimulation provided by hens’ excursions from the nest, is insufficient to produce these effects.

Social enrichment is increasingly employed to improve the welfare of laboratory animals, including rabbits. However, the high levels of injurious aggression that can occur when unfamiliar adult rabbits are introduced to one another are a barrier to implementing social housing. One factor that could affect aggressive interaction is the size of the enclosure in which the animals are introduced, although this has never been tested in rabbits. We evaluated the aggressive and affiliative behavior of 11 pairs of unfamiliar adult female New Zealand White rabbits during 1-h trials. Using a balanced repeated measures design, pairs were tested in a smaller (Small) enclosure the size of a double cage (0.76 m × 1.22 m × 0.61 m) and a larger (Large) enclosure (1.22 m × 1.22 m × 0.61 m), both of which contained PVC barriers that allowed contact but prevented injury. There were no main effects of treatment or treatment order on aggressive or affiliative behavior, but there were significant interaction effects (P = 0.01). During their first trial, pairs tested in the Large enclosure showed higher levels (P = 0.07) of affiliative behavior (mean number = 37.6 ± 5.0) and lower levels (P = 0.02) of aggressive behavior (back-transformed mean number = 1.1) than pairs tested in the Small enclosure (20.7 ± 3.0 and 3.5, respectively). During their second trials, pairs behaved as they did during their first trial, resulting in the opposite pattern: significantly more aggressive behavior in the Large enclosure than the Small enclosure (P = 0.002). In total, there were 47 bites observed among does first introduced in the Small enclosure, as compared to only one in the pairs first introduced in the Large enclosure. Overall, these findings indicate that the Large enclosure was effective at reducing aggression when rabbits were unfamiliar to one another, but that behavior during a subsequent interaction was determined by prior experience rather than enclosure size. More research is needed to determine whether does’ short-term behavior in an experimental apparatus is predictive of long-term pair housing success.

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.

Multi-institutional studies of welfare have proven to be valuable in zoos but are hampered by limited sample sizes and difficulty in evaluating more than just a few welfare indicators. To more clearly understand how interactions of husbandry factors influence the interrelationships among welfare outcomes, epidemiological approaches are needed as well as multifactorial assessments of welfare. Many questions have been raised about the housing and care of elephants in zoos and whether their environmental and social needs are being met in a manner that promotes good welfare. This article describes the background and rationale for a large-scale study of elephant welfare in North American zoos funded by the (U.S.) Institute of Museum and Library Services. The goals of this project are to document the prevalence of positive and negative welfare states in 291 elephants exhibited in 72 Association of Zoos and Aquariums zoos and then determine the environmental, management, and husbandry factors that impact elephant welfare. This research is the largest scale nonhuman animal welfare project ever undertaken by the zoo community, and the scope of environmental variables and welfare outcomes measured is unprecedented.

Furnished cages for laying hens often contain an Astroturf (AT) pad which may be sprinkled with feed to promote foraging and dustbathing. We evaluated AT and AT plus feed (ATF) to determine if hens use these substrates for dustbathing. Hens ( N = 30) without prior exposure to substrate were housed singly in cages at 34 weeks of age. Using a 3 × 3 Latin square design, groups of 10 hens were provided with a dustbox containing either sand (control), an AT pad, or an AT pad with 200 g of feed (ATF) delivered daily, with three 20-day treatment Periods. The treatment order was: sand–ATF–AT (1); ATF–AT–sand (2); AT–sand–ATF (3). Behavior was recorded for 8 or 9 days each Period, from 11:00 to 22:00 h. Three measures of dustbathing were evaluated: bout number per day, bout length, and total time spent dustbathing per day. Data were collected and processed to evaluate dustbathing activity in the substrate, on the wire floor and in both locations combined (overall). Data were analyzed using the GLM or Kruskal–Wallis and Dwass-Steel-Critchlow-Fligner tests. Although there were some differences in statistical significance between Periods, in general hens provided with sand exhibited fewer bouts both overall and on wire, and longer bouts both overall and one wire, than AT or ATF hens, and longer bouts both overall and in substrate than AT. Hens with sand also spent significantly (all P ≤ 0.04) more time dustbathing on substrate (median min = 18.71 ± 5.16) and less time on wire (0.59 ± 1.56) than AT (0.33 ± 2.62 and 13.39 ± 7.15, respectively) and ATF (2.05 ± 4.43 and 11.26 ± 4.37, respectively) treatments during Period 1, and also more time dustbathing on substrate (7.66 ± 8.13) than hens in the AT treatment (0.00 ± 2.52) during Period 2. Exposure to AT and ATF during the first two treatment periods reduced hens’ use of sand during the third treatment period, with only 11% of bouts occurring in sand during Period 3 as compared to 64% and 41% during Periods 1 and 2, respectively. These findings demonstrated that AT did not provide an adequate dustbathing substrate, even with the addition of feed, as hens were less likely to dustbathe on both AT and ATF than sand, and were also less likely to dustbathe on sand if they were initially exposed to AT and ATF as dustbathing substrates.

Because of increasing public concerns about the close confinement of hens associated with cage housing, the global egg industry is undergoing major changes. Conventional cages, the dominant model for egg production since the 1950s, were banned in the European Union effective 2012. In other developed countries, pressure from animal welfare non-governmental organizations or other food system stakeholders (like retailers) is similarly resulting in a large-scale move away from conventional cages toward other systems that provide hens with more behavioral opportunities than conventional cages. In contrast, there is a move toward further intensification of egg production in developing countries, where consumption of animal protein is increasing. But which egg production systems are sustainable? If there are heightened sustainability risks in particular systems, can these be mitigated or eliminated? In this chapter, we review research related to the sustainability of laying hen production systems, with a particular focus on hen welfare, environmental considerations, worker health and safety, economics, and egg quality and safety.

The egg industry is moving away from the use of conventional cages to enriched cage and noncage laying hen housing systems because of animal welfare concerns. In this study, the prevalence and severity of lesions in noncage laying hens from commercial farms in two of the largest egg-producing states, California and Iowa, were evaluated by postmortem examination. Hens that died or were culled were collected during early, mid, and late stages of the laying cycle from 16 houses on three farms. Of the 25 gross lesions identified for study, 22 were observed, with an average of four lesions per hen. Vent cannibalism, reduced feather cover, keel bone deformation, and beak abnormalities were the most frequent lesions, observed in ≥40% of hens. Other common lesions were cloacal prolapse (30.5%), footpad dermatitis (24.3%), and septicemia (23.1%). Beak abnormality and enteric disease had the highest proportion of severe lesions. Pearson chi-square analysis revealed a number of stage-of-lay effects (P ≤ 0.05), some of which differed by state. For both states combined, the lesions observed more frequently during early lay were beak abnormalities, northern fowl mite infestation, and cage layer fatigue, whereas during mid lay, they were poor feather cover, vent cannibalism, footpad dermatitis, keel bone deformation, respiratory disease and roundworms. Feather pecking and cloacal prolapse were most common during late lay. Although differences in hen genetics, farm management practices, and environmental factors could all have affected the results of this study, the information provides a better understanding of hen health in noncage housing systems and could help to identify potential interventions to reduce hen welfare problems.

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

Pre-clinical investigation of human CNS disorders relies heavily on mouse models. However these show low predictive validity for translational success to humans, partly due to the extensive use of rapid, high-throughput behavioral assays. Improved assays to monitor rodent behavior over longer time scales in a variety of contexts while still maintaining the efficiency of data collection associated with high-throughput assays are needed. We developed an apparatus that uses radio frequency identification device (RFID) technology to facilitate long-term automated monitoring of the behavior of mice in socially or structurally complex cage environments. Mice that were individually marked and implanted with transponders were placed in pairs in the apparatus, and their locations continuously tracked for 24 h. Video observation was used to validate the RFID readings. The apparatus and its associated software accurately tracked the locations of all mice, yielding information about each mouse's location over time, its diel activity patterns, and the amount of time it was in the same location as the other mouse in the pair. The information that can be efficiently collected in this apparatus has a variety of applications for pre-clinical research on human CNS disorders, for example major depressive disorder and autism spectrum disorder, in that it can be used to quantify validated endophenotypes or biomarkers of these disorders using rodent models. While the specific configuration of the apparatus described here was designed to answer particular experimental questions, it can be modified in various ways to accommodate different experimental designs.

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.

To encourage nest use in breeder poultry flocks, it is important that nest boxes are attractive. Few studies have evaluated factors affecting nest attractiveness to ducks. We assessed the effects of nest box experience (Experiments 1 and 2) and features of nests, including degree of enclosure (Experiments 1 and 2) and the presence of an egg (Experiment 3), on nest site selection by sexually mature Pekin ducks. The hens were tested individually in pens containing different nest box choices. Nest preferences were determined based on the locations of 14 successively laid eggs. Ducks in Experiment 1 were provided with nest box access prior to the onset of lay (20 weeks of age, EXP group, N = 12) or at the time of preference testing (35 weeks of age, DELAYED-EXP group, N = 12). Delaying nest box access by 15 weeks did not significantly affect the proportion of eggs laid in nest boxes rather than on the floor ( P = 0.40). Regardless of experience ducks laid more than 66% of their eggs in nest boxes offering a higher degree of enclosure. Ducks in Experiment 2 were reared with either open-top (OP, N = 12) or closed-top (CL, N = 12) boxes. Regardless of rearing condition, ducks preferred boxes with the highest level of enclosure offered. Ducks laid twice the expected proportion (25%) of eggs in CL boxes with curtains ( P = 0.0004). CL boxes without curtains were used as predicted by chance, 25% ( P = 0.746), while OP boxes with ( P = 0.009) and without ( P = 0.015) curtains each contained only half the expected number of eggs. Ducks in Experiment 3 were provided with two nest boxes, one of which contained the egg laid the previous day. Each day, the newly laid egg was marked and either placed back in the nest box where it was found (HANDLED, N = 12) or moved into the adjacent nest box (MOVED, N = 12). Ducks in HANDLED and MOVED laid 97.6% and 79.8%, respectively, of their eggs in boxes containing the previous day's egg. While ducks in HANDLED were consistent in their choice throughout the test, those in MOVED developed the preference over time ( P = 0.039), suggesting that the preference for laying in a nest containing an egg may be influenced by experience. These results indicate that nest box enclosure and the presence of an egg are important in determining the nesting choices of Pekin ducks. Incorporating these features into nest boxes may be useful for increasing consistency of nest use in breeder duck flocks.

1. The effect of light intensity on behavioural synchrony and rest in broilers was investigated by randomly assigning 504 Cobb chicks to environmental chambers at low (5 lux), moderate (50 lux), or high (200 lux) daytime illumination under a 16 h L : 8 h D light cycle. We hypothesised that behavioural synchrony and resting behaviour would be affected by light : dark amplitude, and predicted that broilers reared at higher intensities would show increased synchrony and thus have fewer, but longer, resting bouts during the scotophase, since these bouts would be less likely to be interrupted by active birds. 2. Digital recordings were made for 48 h from weeks 3 to 5 of age, and scan samples taken of 11 behaviours at 15-min intervals. Z-scores for the amount of synchronisation were calculated using the kappa coefficient of agreement. Frequency and length of resting bouts and the number of resting bout interruptions by flockmates were also calculated from continuous observations of 4 focal broilers per pen. 3. Resting and sitting behaviour were significantly synchronised or showed a strong trend towards synchronisation in all treatments during the 3 weeks of observation. There were significant treatment differences in the degree of synchrony for preen, eat, rest and forage, with broilers reared in 200 lux showing the greatest degree of synchrony. 4. During the scotophase, broilers reared with high illumination had fewer, longer, and less interrupted bouts of resting than those reared with moderate or low illumination. During the photophase, broilers in the low-illumination treatment had more frequent, longer, and more interrupted resting bouts than those in the moderate or high illumination treatment. 5. In conclusion, rearing broilers under a 16 h L : 8 h D photoperiod with high daytime light intensity resulted in greater behavioural synchrony in the flock, with the potential to improve welfare by increasing uninterrupted resting behaviour during the dark phase.

Light management is a critical component of production for intensively housed animals. To increase productivity, broiler chickens are often raised commercially in houses that are dimly illuminated on a near-continuous basis. There have been relatively few studies examining the effects of light intensity on the behaviour of broilers. We evaluated the time budgets of broilers (N = 464) housed under one of three photophase light levels (5, 50 or 200 lx) chosen to produce low, moderate or high illumination contrasts with the scotophase light level (1 lx). There were four replicate pens of broilers per treatment. We recorded behaviour for 48 continuous hours during weeks 3, 4, and 5 of age and analysed the time broilers spent exhibiting eight behaviours and two behavioural categories (inactive and active) during the overall photoperiod, photophase and scotophase. There were only two main effects of light intensity on behaviour during the overall photoperiod: 5 lx broilers preened and foraged less than the 50 (P = 0.03, P = 0.03, respectively) and 200 lx birds (P

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.

Environmental enrichment is an important strategy to improve the welfare of laboratory animals. Running wheels might serve as enrichment devices for laboratory mice, since mice use them extensively when they are provided. However, competition among group-housed mice for such highly preferred enrichment devices could also lead to injurious aggression. We therefore assessed the effects of providing a running wheel-igloo enrichment on the social behaviour of group-housed male mice. CD-1 (ICR) mice (n = 60, 20 per treatment) were housed in standard polycarbonate cages (five mice per cage) for 2 weeks (BASE), and then placed in either: (1) a standard cage with bedding (CONTROL), or (2) same as CONTROL, but with the addition of a Bio-Serv® mouse running wheel-igloo (WHEEL) or (3) same as WHEEL, but with the running wheel glued in place so that it could not rotate (FIXED). Social behaviour and dominance ranks were assessed at the end of BASE and 2 weeks after imposition of treatments. There was increased escalated aggression in both enriched cages (FIXED, Tukey: T8 = −8.31; P = 0.0003; WHEEL, Tukey: T8 = −4.577; P = 0.0153), and decreased stereotypy in WHEEL (Tukey: T8 = 4.226; P = 0.0237). There was also a decrease in dominance hierarchy linearity in enriched treatments (FIXED, Tukey: T9 = 3.653; P = 0.0433; WHEEL, Tukey: T9 = 6.273; P = 0.0014) and a negative correlation between hierarchy linearity and escalated aggression overall (GLM: F1,7 = 61.41; P < 0.001; partial r = 0.90). Thus, providing the running wheel-igloo enrichment had a negative effect in that it increased potentially injurious aggression. Additionally, the decrease in hierarchy linearity suggests that the social structure in enriched groups was disrupted. The cause of the decrease in cage stereotypies in WHEEL is unknown, but could be because these stereotypies were re-directed towards stereotypic wheel-running, or because wheel-running reduced frustration due to limited opportunities for exploratory locomotion or caused a shift in the behavioural time budget. Despite this decrease in stereotypy, this form of enrichment is not beneficial for group-housed male CD-1 mice due to the associated increased aggression. However, female mice or males of less aggressive mouse strains might respond differently, and singly housed mice should generally benefit from such enrichment.

What impact has the Brambell Report, and the growth of the field of applied ethology, had on the United States of America? There has been increasing public awareness of farm animal welfare issues and a concomitant increase in animal welfare research and teaching activities. This has occurred more slowly in the U.S.A. than in Europe, but is now gathering momentum as the agricultural industries and food retailers write guidelines and implement animal welfare auditing programs in an attempt to reassure consumers that farm animals are raised and slaughtered humanely. Applied ethologists have played an important role in these advances, not just in terms of providing relevant scientific research results, but also as consultants and members of advisory committees. This is likely to continue, although the long-term effectiveness of depending upon voluntary standards and auditing programs to foster sustained industry-wide improvements in farm animal welfare and to reassure consumers remains to be seen.

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

In commercial production facilities, ducks are often bill-trimmed to prevent feather pecking and cannibalism. Beak-trimming of chickens and turkeys has been criticized because of its potential to cause acute and chronic pain, but little is known about the effects of bill-trimming on the welfare of ducks. We conducted a study to determine the effects of a commercial bill-trimming method, cutting without cautery, on the behavior and bill morphopathology of ducks. Muscovy ducks were housed in six pens each containing 16 ducks (eight males and eight females). Three pens of ducks were trimmed (TRIM) using scissors at 20 days post-hatch, while ducks in the remaining three pens were sham-trimmed (NOTRIM). The average length removed from the upper bill was 0.51cm, or 21.1% of the bill length from nares to tip. The behavior of all ducks was recorded during the first week post-trim using scan sampling. In addition, two ducks/sex/pen were randomly selected as focal birds, and observed using 15-min focal samples during the morning (0900–1100) and afternoon (1200–1500) for 7 weeks post-trim. Ducks were weighed weekly. Behavioral and body weight data were analyzed using the General Linear Model. At 12 weeks of age, the male focal ducks were killed and their bills were then collected and subjected to gross and morphopathological analysis. In the days immediately post-trim, TRIM ducks spent significantly less ( p p =0.0064) than NOTRIM, but there was no treatment difference in weights by 2 weeks post-trim. By 6 weeks post-trim the upper bill of TRIM was only 11.9% shorter than the lower bill. There was evidence of feather pecking in the TRIM pens, but feather pecking and skin damage were more extensive in the NOTRIM pens. The TRIM bill stumps were covered with epithelium, lacked blood vessels and showed evidence of scarring, but there were no neuromas. These results are consistent with this bill-trimming method causing acute, but not chronic, pain in Muscovy ducks.

Cognitive mechanisms are an important part of the organization of the behavior systems of animals. In the wild, animals regularly face problems that they must overcome in order to survive and thrive. Solving such problems often requires animals to process, store, retrieve, and act upon information from the environment—in other words, to use their cognitive skills. For example, animals may have to use navigational, tool-making or cooperative social skills in order to procure their food. However, many enrichment programs for captive animals do not include the integration of these types of cognitive challenges. Thus, foraging enrichments typically are designed to facilitate the physical expression of feeding behaviors such as food-searching and food consumption, but not to facilitate complex problem solving behaviors related to food acquisition. Challenging animals by presenting them with problems is almost certainly a source of frustration and stress. However, we suggest here that this is an important, and even necessary, feature of an enrichment program, as long as animals also possess the skills and resources to effectively solve the problems with which they are presented. We discuss this with reference to theories about the emotional consequences of coping with challenge, the association between lack of challenge and the development of abnormal behavior, and the benefits of stress (arousal) in facilitating learning and memory of relevant skills. Much remains to be done to provide empirical support for these theories. However, they do point the way to a practical approach to improving animal welfare—to design enrichments to facilitate the cognitive mechanisms which underlie the performance of complex behaviors that cannot be performed due to the restrictions inherent to the captive environment.