The Gordon Memorial Lecture: Laying hen welfare.

Preference tests remain a useful tool in the assessment of laying hen welfare and have been used to establish what types of resources and enrichments are most likely to meet the birds' needs. Evidence on the underlying structure of bird preference suggests that hens make stable and reliable choices across time and context. This means that their preferences can also be used as a benchmark in the validation of other welfare indicators. Hens have sophisticated cognitive abilities. They are quick to form associations between events and they are flexible in how they apply their knowledge in different contexts. However, they may not form expectations about the world in the same way as some mammalian species. Limited research in this area to date seems to show that hens judge situations in absolute terms rather than evaluating how a situation may be improving or deteriorating. The proportion of hens housed in cage-free systems is increasing globally, providing birds with greater behavioural freedom. Many of the problems associated with cage-free systems, such as keel bone fractures, mortality and injurious pecking, are slowly reducing due to improved experience and appropriate changes in rearing practices, diet, housing design and alignment of breeding goals. However, much remains to be done. The design and performance of veranda-based systems which provide hens with fresh air and natural light is a promising avenue for future research aimed at optimising hen welfare and improving sustainability.

Expert assessment of the impact of ship-strikes on cetacean welfare using the Welfare Assessment Tool for Wild Cetaceans.

Human activities are increasingly impacting our oceans and the focus tends to be on their environmental impacts, rather than consequences for animal welfare. Global shipping density has quadrupled since 1992. Unsurprisingly, increased levels of vessel collisions with cetaceans have followed this global expansion of shipping. This paper is the first to attempt to consider the severity of ship-strike on individual whale welfare. The methodology of the 'Welfare Assessment Tool for Wild Cetaceans' (WATWC) was used, which is itself based upon the Five Domains model. Expert opinion was sought on six hypothetical but realistic case studies involving humpback whales (Megaptera novaeangliae) struck by ships. Twenty-nine experts in the cetacean and welfare sector took part. They were split into two groups; Group 1 first assessed a case we judged to be the least severe and Group 2 first assessed the most severe. Both groups then additionally assessed the same four further cases. This was to investigate whether the severity of the first case influenced judgements regarding subsequent cases (i.e. expert judgements were relative) or not (i.e. judgements were absolute). No significant difference between the two groups of assessors was found; therefore, the hypothesis of relative scoring was rejected. Experts judged whales may suffer some level (>1) of overall (Domain 5) harm for the rest of their lives following a ship-strike incident. Health, closely followed by Behaviour were found to be the welfare aspects most affected by ship-strikes. Overall, the WATWC shows a robust potential to aid decision-making on wild cetacean welfare.

Dairy vs beef production - expert views on welfare of cattle in common food production systems.

Consumers' views and concerns about the welfare of farm animals may play an important role in their decision to consume dairy, meat and/or plants as their primary protein source. As animals are killed prematurely in both dairy and beef industries, it is important to quantify and compare welfare compromises in these two sectors before the point of death. Seventy world-leading bovine welfare experts based in 23 countries were asked to evaluate the likelihood of a bovine to experience 12 states of potential welfare concern, inspired by the Welfare Quality® protocol. The evaluation focused on the most common beef and dairy production systems in the experts' country and was carried out separately for dairy/beef calves raised for red meat, dairy/beef calves raised for veal, dairy/beef calves raised as a replacement, and for dairy/beef cows. The results show experts rated the overall likelihood of a negative welfare state (i.e. welfare risk) to be higher in animals from dairy herds than from beef herds, for all animal categories, regardless of whether they were used to produce milk, red meat or veal. These findings suggest that consuming food products derived from common dairy production systems (dairy or meat) may be more harmful to the welfare of animals than consuming products derived from common beef production systems (i.e. from animals solely raised for their meat). Raising awareness about the linkage between dairy and meat production, and the toll of milk production on the welfare state of animals in the dairy industry, may encourage a more sustainable and responsible food consumption.

The Effect of Hard Pecking Enrichment during Rear on Feather Cover, Feather Pecking Behaviour and Beak Length in Beak-Trimmed and Intact-Beak Laying Hen Pullets.

Injurious pecking, commonly controlled by beak trimming (BT), is a widespread issue in laying hens associated with thwarted foraging. This controlled study compared the effect in intact and beak-trimmed pullets of providing pecking pans to eight treatment flocks from six weeks of age. Flocks (mean size 6843) comprised eight British Blacktail, six Lohmann Brown and two Bovans Brown. All young birds (6−7 weeks) pecked more frequently at the pecking pans (mean 40.4) than older pullets (mean 26.0, 23.3 pecks/bird/min at 10−11 weeks and 14−15 weeks, respectively) (p < 0.005). There was no effect on feather pecking or plumage cover. Mean side-beak length and mean top-beak lengths were shorter in treatment flocks at 6−7 weeks and 10−11 weeks (p < 0.001). Intact-beak treatment flocks had shorter mean side-beak length at 10−11 weeks (p < 0.001) and at 14−15 weeks (p < 0.05) and mean top-beak length at 6−7 weeks (p < 0.05) and at 10−11 weeks (p < 0.05). BT treatment flocks had shorter side-beak and top-beak lengths at 6−7 weeks and at 10−11 weeks (p < 0.001). Beak lengths showed linear growth, with individual bird variation indicating a potential for genetic selection. The study demonstrated that abrasive material can reduce beak length in pullets.

A Citizen Science Trial to Assess Perception of Wild Penguin Welfare.

Wild penguins are facing increased threats to their populations and their welfare as a consequence of human activities. Understanding the perception of animal welfare is essential to identify ethical concerns related to the negative impact of anthropogenic factors on wild species and to guide conservation efforts that reflect societal values. Since penguin conservation is of general interest, we examined the human dimension of welfare assessment across a range of interest groups concerned with penguins, seabird biology and wildlife conservation. We provided participants with a Penguin Welfare Assessment Tool (PWAT) based on the five domains model. The PWAT supports consideration of the impact of four physical aspects on welfare-relevant mental states. Bibliometric analysis of keywords from 347 scientific articles indicated that penguins around the world face five main types (themes) of anthropogenic factors and we then developed five hypothetical scenarios, each related to one theme. Seventy-five participants scored the overall impact of the events described in the scenarios on penguin welfare as negative using the PWAT. Participants rated short-duration, high-intensity events (i.e., being trapped in a ghost fishing net) as having a significantly more severe impact on penguin welfare than low-intensity, long-duration events (P < 0.0001). Scores provided by participants for each domain for each scenario were largely as expected and we found good correlation (all P < 0.0001) between the physical domains and "mental state" for all scenarios, indicating that the tool was facilitating the participants' assessment of welfare. No evidence was found that experience of working or studying penguins, or indeed any other demographic factor investigated, influenced the assessments of welfare. We found little agreement between participants in the scores provided (unalike scores mostly between 0.7 and 0.8), and agreement between participants with experience of working with penguins was no better than between participants without such experience. We discuss the possibility that low agreement within different interest groups may be improved by providing more scientific information to support the evaluation of penguin welfare. We conclude that scientific knowledge of penguin biological responses to anthropogenic factors is vital to support the evaluation of wild penguin welfare by the public and other stakeholders.

Social buffering in horses is influenced by context but not by the familiarity and habituation of a companion.

Social buffering occurs when the presence of one animal attenuates another's stress response during a stressful event and/or helps the subject to recover more quickly after a stressful event. Inconsistent previous results might reflect previously unrecognised contextual influences, such as the nature of the stimulus presented or social factors. We addressed these issues in a two-part study of horses paired with familiar (16 subjects) or unfamiliar (16 subjects) companions. Each subject performed 4 tests in a counterbalanced order: novel object test (static ball)-alone or with companion; and umbrella opening test-alone or with companion. Social buffering was significantly influenced by the nature of the stimulus presented, but not by companion's habituation status or familiarity. Importantly, the stimulus used produced differential effects on behavioural and physiological measures of buffering. A companion significantly reduced behavioural response (reactivity) in the novel object test but not in the umbrella test. However, heart rate recovered more quickly for subjects with a companion in the umbrella test but not in the novel object test. We propose that circumstances which permit greater contextual processing may facilitate demonstration of behavioural effects of social buffering, whereas buffering in response to startling events may be manifest only during post-event physiological recovery.

Rearing experience with ramps improves specific learning and behaviour and welfare on a commercial laying farm.

To access resources in commercial laying houses hens must move between levels with agility to avoid injury. This study considered whether providing ramps during rear improved the ability of birds to transition between levels. Twelve commercial flocks (2000 birds/flock) on a multi-age site were examined between 1 and 40 weeks of age. All birds had access to elevated perching structures from 4 days of age. Six treatment flocks were also provided with ramps during rear to facilitate access to these structures. Flocks were visited three times during rear and three times at lay to record transitioning behaviour and use of the elevated structures, together with scores for keel bone and feather damage. Ramp reared flocks used the elevated structures to a greater extent at rear (P = 0.001) and at lay, when all flocks had ramps, showed less hesitancy [i.e. pacing (P = 0.002), crouching (P = 0.001) and wing-flapping (P = 0.001)] in accessing levels. Mean levels of keel bone damage were reduced in ramp reared flocks (52%) compared with control flocks (64.8%) at 40 weeks of age (P = 0.028). The early life experience of the ramp reared flocks enabled specific learning that translated and persisted in later life and resulted in overall welfare benefits.

Exploratory behaviour towards novel objects is associated with enhanced learning in young horses.

The mechanisms underlying individual variation in learning are key to understanding the development of cognitive abilities. In humans and primates, curiosity has been suggested as an important intrinsic factor that enhances learning, whereas in domesticated species research has primarily identified factors with a negative effect on cognitive abilities, such as stress and fearfulness. This study presents the first evidence of a link between object-directed curiosity and learning performance in young horses in two very different learning tasks (visual discrimination and pressure-release). We exposed young horses (n = 44) to standardised novel object tests at 5 months and 1 year of age and found consistency in responses. Standard indicators of fearfulness (e.g. heart rate and alertness) were unrelated to learning performance, whereas exploratory behaviour towards the novel objects correlated to performance in both learning tasks. Exploratory behaviour was unreinforced in the novel object tests and likely reflects the animal's intrinsic motivation (i.e. curiosity), suggesting that this trait is favourable for learning performance. In addition to the insights that these results provide into cognition in a domesticated species, they also raise questions in relation to fostering of curiosity in animals and the impact that such manipulation may have on cognitive abilities.

From Unpleasant to Unbearable-Why and How to Implement an Upper Limit to Pain and Other Forms of Suffering in Research with Animals.

The focus of this paper is the requirement that the use of live animals in experiments and in vivo assays should never be allowed if those uses involve severe suffering. This requirement was first implemented in Danish legislation, was later adopted by the European Union, and has had limited uptake in North America. Animal suffering can arise from exposure to a wide range of different external and internal events that threaten biological or social functions, while the severity of suffering may be influenced by the animals' perceptions of their own situation and the degree of control they are able to exert. Severe suffering is more than an incremental increase in negative state(s) but involves a qualitative shift whereby the normal mechanisms to contain or keep negative states at arm's length no longer function. The result of severe suffering will be a loss of the ability of cope. The idea of putting a cap on severe suffering may be justified from multiple ethical perspectives. In most, if not all, cases it is possible to avoid imposing severe suffering on animals during experiments without giving up the potential benefits of finding new ways to cure, prevent, or alleviate serious human diseases and generate other important knowledge. From this it follows that there is a strong ethical case to favor a regulatory ban on animal experiments involving severe suffering.

Foraging efficiency, social status and body condition in group-living horses and ponies.

Individual animals experience different costs and benefits associated with group living, which may impact on their foraging efficiency in ways not yet well specified. This study investigated associations between social dominance, body condition and interruptions to foraging behaviour in a cross-sectional study of 116 domestic horses and ponies, kept in 20 discrete herds. Social dominance was measured for each individual alongside observations of winter foraging behaviour. During bouts of foraging, the duration, frequency and category (vigilance, movement, social displacements given and received, scratching and startle responses) of interruptions were recorded, with total interruption time taken as a proxy measure of foraging efficiency. Total foraging time was not influenced by body condition or social dominance. Body condition was associated with social dominance, but more strongly associated with foraging efficiency. Specifically, lower body condition was associated with greater vigilance. This demonstrates that factors other than social dominance can result in stable differences in winter body condition.

Anthropogenic Threats to Wild Cetacean Welfare and a Tool to Inform Policy in This Area.

Human activities and anthropogenic environmental changes are having a profound effect on biodiversity and the sustainability and health of many populations and species of wild mammals. There has been less attention devoted to the impact of human activities on the welfare of individual wild mammals, although ethical reasoning suggests that the welfare of an individual is important regardless of species abundance or population health. There is growing interest in developing methodologies and frameworks that could be used to obtain an overview of anthropogenic threats to animal welfare. This paper shows the steps taken to develop a functional welfare assessment tool for wild cetaceans (WATWC) via an iterative process involving input from a wide range of experts and stakeholders. Animal welfare is a multidimensional concept, and the WATWC presented made use of the Five Domains model of animal welfare to ensure that all areas of potential welfare impact were considered. A pilot version of the tool was tested and then refined to improve functionality. We demonstrated that the refined version of the WATWC was useful to assess real-world impacts of human activity on Southern Resident killer whales. There was close within-scenario agreement between assessors as well as between-scenario differentiation of overall welfare impact. The current article discusses the challenges raised by assessing welfare in scenarios where objective data on cetacean behavioral and physiological responses are sparse and proposes that the WATWC approach has value in identifying important information gaps and in contributing to policy decisions relating to human impacts on whales, dolphins, and porpoises.

The impact of early structural enrichment on spatial cognition in layer chicks.

The aim of the study was to determine whether early access to elevated structures affects spatial navigational abilities. Ninety six day-old chicks were reared in 16 pens. Eight pens were provided with A-frame perches with an attached platform and a ramp. Eight pens had no elevated structures. At 14-15 days of age 48 chicks were tested in a battery of navigational tasks: a detour test, jump test and rotated floor test (RFT). The remaining 48 chicks received the same tests at 28-29 days of age. Chicks reared with elevated structures were faster at completing the detour test (P = 0.045). Older chicks were more likely to turn left in the detour test (p = 0.013) and were more successful in the jump test (69% vs 31% completion, p = 0.001). There was no treatment effect on use of intra or extra-maze cues in the RFT, but the proportion of chicks using intra-maze cues declined between the first (0.76) and second (0.43) repeat of the RFT (p = 0.038), particularly for chicks reared with elevated structures. We conclude that bird age or developmental stage may have a predominant influence on spatial navigation and physical ability, but early experience of elevated structures had some mediating effects which require further investigation.

Examining affective structure in chickens: valence, intensity, persistence and generalization measured using a Conditioned Place Preference Test.

When measuring animals' valenced behavioural responses to stimuli, the Conditioned Place Preference (CPP) test goes a step further than many approach-based and avoidance-based tests by establishing whether a learned preference for, or aversion to, the location in which the stimulus was encountered can be generated. We designed a novel, four-chambered CPP test to extend the capability of the usual CPP paradigm to provide information on four key features of animals' affective responses: valence, scale, persistence and generalization. Using this test, we investigated the affective responses of domestic chickens (Gallus gallus domesticus) to four potentially aversive stimuli: 1. Puffs of air; 2. Sight of (robotic) snake; 3. Sprays of water; 4. Sound of conspecific alarm calls. We found conditioned avoidance of locations associated with the air puffs and water sprays (Friedman's χ2 (3) = 13.323 p > .005; χ2 (3) = 14.235 p > .005), but not with the snake and alarm calls. The scale of the learned avoidance was similar for the air puff and water spray stimuli, but persistence and generalization differed. We conclude that the four chambered CPP test can have a valuable role to play in making multi-feature measurements of stimulus-generated affective responses, and we highlight the value of such measurements for improving our understanding of the structure of affect in chickens and other animals.

Socially-mediated arousal and contagion within domestic chick broods.

Emotional contagion - an underpinning valenced feature of empathy - is made up of simpler, potentially dissociable social processes which can include socially-mediated arousal and behavioural/physiological contagion. Previous studies of emotional contagion have often conflated these processes rather than examining their independent contribution to empathic response. We measured socially-mediated arousal and contagion in 9-week old domestic chicks (n = 19 broods), who were unrelated but raised together from hatching. Pairs of observer chicks were exposed to two conditions in a counterbalanced order: air puff to conspecifics (AP) (during which an air puff was applied to three conspecifics at 30 s intervals) and control with noise of air puff (C) (during which the air puff was directed away from the apparatus at 30 s intervals). Behaviour and surface eye temperature of subjects and observers were measured throughout a 10-min pre-treatment and 10-min treatment period. Subjects and observers responded to AP with increased freezing, and reduced preening and ground pecking. Subjects and observers also showed reduced surface eye temperature - indicative of stress-induced hyperthermia. Subject-Observer behaviour was highly correlated within broods during both C and AP conditions, but with higher overall synchrony during AP. We demonstrate the co-occurrence of socially-mediated behavioural and physiological arousal and contagion; component features of emotional contagion.

Retrospective harm benefit analysis of pre-clinical animal research for six treatment interventions.

BACKGROUND: The harm benefit analysis (HBA) is the cornerstone of animal research regulation and is considered to be a key ethical safeguard for animals. The HBA involves weighing the anticipated benefits of animal research against its predicted harms to animals but there are doubts about how objective and accountable this process is. OBJECTIVES: i. To explore the harms to animals involved in pre-clinical animal studies and to assess these against the benefits for humans accruing from these studies; ii. To test the feasibility of conducting this type of retrospective HBA. METHODS: Data on harms were systematically extracted from a sample of pre-clinical animal studies whose clinical relevance had already been investigated by comparing systematic reviews of the animal studies with systematic reviews of human studies for the same interventions (antifibrinolytics for haemorrhage, bisphosphonates for osteoporosis, corticosteroids for brain injury, Tirilazad for stroke, antenatal corticosteroids for neonatal respiratory distress and thrombolytics for stroke). Clinical relevance was also explored in terms of current clinical practice. Harms were categorised for severity using an expert panel. The quality of the research and its impact were considered. Bateson's Cube was used to conduct the HBA. RESULTS: The most common assessment of animal harms by the expert panel was 'severe'. Reported use of analgesia was rare and some animals (including most neonates) endured significant procedures with no, or only light, anaesthesia reported. Some animals suffered iatrogenic harms. Many were kept alive for long periods post-experimentally but only 1% of studies reported post-operative care. A third of studies reported that some animals died prior to endpoints. All the studies were of poor quality. Having weighed the actual harms to animals against the actual clinical benefits accruing from these studies, and taking into account the quality of the research and its impact, less than 7% of the studies were permissible according to Bateson's Cube: only the moderate bisphosphonate studies appeared to minimise harms to animals whilst being associated with benefit for humans. CONCLUSIONS: This is the first time the accountability of the HBA has been systematically explored across a range of pre-clinical animal studies. The regulatory systems in place when these studies were conducted failed to safeguard animals from severe suffering or to ensure that only beneficial, scientifically rigorous research was conducted. Our findings indicate a pressing need to: i. review regulations, particularly those that permit animals to suffer severe harms; ii. reform the processes of prospectively assessing pre-clinical animal studies to make them fit for purpose; and iii. systematically evaluate the benefits of pre-clinical animal research to permit a more realistic assessment of its likely future benefits.

Using the Five Domains Model to Assess the Adverse Impacts of Husbandry, Veterinary, and Equitation Interventions on Horse Welfare.

The aim of this study was to conduct a series of paper-based exercises in order to assess the negative (adverse) welfare impacts, if any, of common interventions on domestic horses across a broad range of different contexts of equine care and training. An international panel (with professional expertise in psychology, equitation science, veterinary science, education, welfare, equestrian coaching, advocacy, and community engagement; n = 16) met over a four-day period to define and assess these interventions, using an adaptation of the domain-based assessment model. The interventions were considered within 14 contexts: C1 Weaning; C2 Diet; C3 Housing; C4 Foundation training; C5 Ill-health and veterinary interventions (chiefly medical); C6 Ill-health and veterinary interventions (chiefly surgical); C7 Elective procedures; C8 Care procedures; C9 Restraint for management procedures; C10 Road transport; C11 Activity-competition; C12 Activity-work; C13 Activity-breeding females; and C14 Activity-breeding males. Scores on a 1-10 scale for Domain 5 (the mental domain) gathered during the workshop were compared with overall impact scores on a 1-10 scale assigned by the same panellists individually before the workshop. The most severe (median and interquartile range, IQR) impacts within each context were identified during the workshop as: C1 abrupt, individual weaning (10 IQR 1); C2 feeding 100% low-energy concentrate (8 IQR 2.5); C3 indoor tie stalls with no social contact (9 IQR 1.5); C4 both (i) dropping horse with ropes (9 IQR 0.5) and forced flexion (9 IQR 0.5); C5 long-term curative medical treatments (8 IQR 3); C6 major deep intracavity surgery (8.5 IQR 1); C7 castration without veterinary supervision (10 IQR 1); C8 both (i) tongue ties (8 IQR 2.5) and (ii) restrictive nosebands (8 IQR 2.5); C9 ear twitch (8 IQR 1); C10 both (i) individual transport (7.00 IQR 1.5) and group transport with unfamiliar companions (7 IQR 1.5); C11 both (i) jumps racing (8 IQR 2.5) and Western performance (8 IQR 1.5); C12 carriage and haulage work (6 IQR 1.5); C13 wet nurse during transition between foals (7.5 IQR 3.75); and C14 teaser horse (7 IQR 8). Associations between pre-workshop and workshop scores were high, but some rankings changed after workshop participation, particularly relating to breeding practices. Domain 1 had the weakest association with Domain 5. The current article discusses the use of the domain-based model in equine welfare assessment, and offers a series of assumptions within each context that future users of the same approach may make when assessing animal welfare under the categories reported here. It also discusses some limitations in the framework that was used to apply the model.

Behavioural and physiological responses of laying hens to automated monitoring equipment.

Automated monitoring of behaviour can offer a wealth of information in circumstances where observing behaviour is difficult or time consuming. However, this often requires attaching monitoring devices to the animal which can alter behaviour, potentially invalidating any data collected. Birds often show increased preening and energy expenditure when wearing devices and, especially in laying hens, there is a risk that individuals wearing devices will attract aggression from conspecifics. We studied the behavioural and physiological response of 20 laying hens to backpacks containing monitoring devices fastened with elastic loops around the wing base. We hypothesised that backpacks would lead to a stress-induced decrease in peripheral temperature, increased preening, more aggression from conspecifics, and reduced bodyweights. This was evaluated by thermography of the eye and comb (when isolated after fitting backpacks), direct observations of behaviour (when isolated, when placed back into the group, and on later days), and weighing (before and after each 7-day experimental period). Each hen wore a backpack during one of the two experimental periods only and was used as her own control. Contrary to our hypothesis, eye temperature was higher when hens wore a backpack (No backpack: 30.2 °C (IQR: 29.0-30.6) vs. Backpack: 30.9 °C (IQR: 30.0-32.0), P < 0.001). Eye temperature of hens wearing a backpack was strongly correlated to the time spent preening (rs = 0.8, P < 0.001), suggesting that the higher temperatures may have been due to preening itself, or to a low head position or decreased heat dissipation when preening under the wings. Aggressive behaviour was very rare and no effect of the backpacks was found. In line with our hypothesis, backpacks increased preening on the day of fitting, both when isolated (No backpack: 0% (IQR: 0-1) vs. Backpack: 22% (IQR: 1-43), P < 0.01) and when back in the group (No backpack: 0% (IQR: 0-27) vs. Backpack: 43% (IQR: 5-77), P < 0.001). However, no effect on preening was observed 2-7 days afterwards. Other behavioural changes suggested that on the day of fitting hens prioritized attempts to (re)move the backpack and were less attentive to their surroundings. However, only equipment pecking (i.e., pecking the backpack or leg rings) was still affected 2-7 days after fitting (No backpack: 0 pecks/hen/minute (IQR: 0-0), vs. Backpack: 0 (IQR: 0-0.07), P < 0.05). We found no effect of our backpacks on bodyweight. In conclusion, our backpacks seem suitable to attach monitoring equipment to hens with only a very minor effect on their behaviour after a short acclimation period (≤2 days).

The ability of laying pullets to negotiate two ramp designs as measured by bird preference and behaviour.

BACKGROUND: Laying hens are often kept in barn or free-range systems where they must negotiate level changes in the house to access resources. However, collisions and resultant keel fractures are commonplace. Producers sometimes add ramps to make raised areas more accessible but designs vary and very little research has investigated bird preference or behaviour when using different ramp designs, or the effect of ramp design on falls and collisions. METHODS: Two ramp designs were studied in an experimental setting-a ramp made of plastic poultry slats (grid ramp, GR) and a ramp made of wooden rungs (ladder ramp, LR). Sixty-four young female hens were trained to move to a food reward and this was used to test their behavioural responses when first negotiating the two different ramps during individual tests. Both upward and downward transitions were studied. Ramp preference was also tested using a room that replicated a commercial single-tier system with both types of ramp available. Birds were placed in this room in groups of 16 for three days and their use of the ramps studied. RESULTS: A greater percentage of birds successfully completed (reached the reward bowl) on the GR than the LR during both upward (58% vs 37%) and downward (83% vs 73%) transitions, and a smaller percentage of birds made zero attempts to use the GR than the LR (upwards: 13% vs 56%, downwards: 8% vs 26%). When making a downward transition, more hesitation behaviours were seen (head orientations, stepping on the spot, moving away) for the LR. However, more head orientations were seen for the GR during the upward transition. Birds were more likely to abort attempts (an attempt began when a bird placed both feet on the ramp) to move up the GR than the LR. Birds took longer to negotiate the LR than the GR in both directions, and more pauses were seen during a successful upward transition on the LR. Birds were more likely to move down the GR by walking/running whereas birds tended to jump over the entire LR. More collisions with the food reward bowl were seen for the LR. In the group tests, birds preferred to use the GR, with more transitions seen at all timepoints. However, in these tests, birds preferred to rest on the LR with greater numbers of birds counted on this type of ramp during scan sampling at all timepoints. DISCUSSION: Behavioural results suggest that the GR was easier for the birds to use than the LR, particularly on the downward transition. The GR was also less likely to result in collisions. However, the upward transition may be more difficult on the GR for some birds, potentially because of the inability to pause on a level surface during the transition. The results suggest that the GR was preferred by pullets for moving between a raised area and the ground but the LR was preferred for resting.

Rearing Laying Hens in Aviaries Reduces Fearfulness following Transfer to Furnished Cages.

Appropriate rearing is essential for ensuring the welfare and productivity of laying hens. Early experience has the potential to affect the development of fearfulness. This study tested whether rearing in aviaries, as opposed to cages, reduces the fearfulness of laying hens after transfer to furnished cages. Fear responses were recorded as avoidance of a novel object in the home cage. Lohmann Selected Leghorns were reared in an aviary system or conventional rearing cages and then transported to furnished cages at 16 weeks, before the onset of lay. Observations of a selection of birds were conducted at 19 (N = 50 independent cages) and 21 (N = 48 independent cages) weeks of age. At 19 and 21 weeks, cage-reared birds showed higher levels of fearfulness indicated by spending more time away from the novel object compared to aviary-reared birds. These results suggest that rearing in an enriched aviary environment reduces fearfulness up to the fifth week after transfer to a new housing system, compared to rearing in cages.

Effect of reward downshift on the behaviour and physiology of chickens.

When a reward is downgraded in quantity or quality from that which is expected, one of two possible outcomes can result. Acquisition responses may decline gradually, owing to a strong stimulus-response reinforcement history, and thus follow the Thorndikian law of effect. Alternatively, there may be an exaggerated reaction to a downgraded reward when it is initially altered, compared to the behaviour of individuals that have always been trained to receive the lower magnitude reward; this is known as successive negative contrast (SNC). While behavioural SNC effects have been commonly demonstrated in mammals, evidence that they occur in other taxa is more equivocal. Additionally, studies demonstrating immediate physiological reactions during reward downshifts are limited. We investigated the reaction of chickens, Gallus gallus domesticus, to a downshift in the quality of a food reward that they had been trained to expect in a runway apparatus. During a preshift phase, 16 chickens (control) were given food that was flavoured to make it less preferred, while the other 16 (contrast) were fed the same food but without flavouring. During trial 7, unflavoured food was substituted by flavoured food for contrast hens and all birds were fed the flavoured food during a postshift phase. In the contrast group, food consumption immediately decreased and heart rate increased when the reward was downshifted from unflavoured to flavoured food, but there was no evidence of SNC effects, which could stem from methodological or taxonomic differences from previous studies. The latency to reach the food appeared to follow the Thorndikian law of effect, gradually increasing following the downshift. We suggest that the disparity between the pattern shown by the latency results and other measures could relate to the time period in which measures were taken, as acquisition responses are more likely to follow the law of effect.