Cm Sherwin

The use and perceived importance of three resources which provide caged laboratory mice the opportunity for extended locomotion

Abstract Several species of animal are routinely housed in small, barren cages with little opportunity for extended or complex locomotion. Various resources could be provided to overcome this limitation, however, these differ in their practicality, cost and presumably in their suitability as perceived by the animal. This study examined the activity of 5 laboratory mice within three resources which provided the opportunity for extended or complex locomotion, namely, a ‘locomotion-loop’ (a 40 cm torus of plastic tunnel), a complex tunnel environment and a running-wheel. In addition, the perceived importance of these resources was determined by measuring the persistence of their use when the operant cost (switch pressing) of gaining access was increased. When the lowest cost of 1 press/visit was imposed, the mice used the three resources to different extents: the running-wheel was used for the greatest proportion of each 24 h (9.1%), the tunnel system was used for an intermediate amount of time (8.1%) and the loop was used the least (0.3%) (all differences were significant). At the lowest cost the running-wheel was visited 13.7 times each 24 h, the tunnels 14.6 times and the loop only 4.7 times. Over the 15-day duration of the study, the mice reduced the frequency of visits and activity in the loop and tunnel system, but not the running-wheel, i.e. the mice habituated to the loop and tunnels, but not the running-wheel. When the cost of access was increased, the frequency of visits decreased for all three resources. However, activity within visits increased and the duration of visits remained constant for the running-wheel, whereas both decreased for the loop or remained constant for the tunnel system. Therefore, as the costs increased within the range studied here, the mice defended the proportion of 24 h in the running-wheel to a greater extent than time in the tunnel system or the loop. Of the 3 resources, use of the running-wheel was least affected by increasing the cost of access, indicating this resource was perceived as the most important. These results in combination with previous investigations indicate that wheel-running is a higly motivated behaviour. The present results show that caged laboratory mice perceived running-wheels to be an important resource and as such, indicate these might be an appropriate form of environmental enrichment.

Social learning influences the preferences of domestic hens for novel food

It has been argued that social learning helps animals either avoid noxious substances or identify food items, but evidence suggests that avian social learning is fundamentally different from that of mammals. In two experiments, we investigated whether the preferences of domestic hens, Gallus g. domesticus, for novel food were influenced by observing the feeding behaviour of conspecifics. In experiment 1, we attempted to confirm that birds can develop socially learnt aversions to unpalatable foods. Despite demonstrators showing a highly visible ‘disgust reaction’ after eating unpalatable coloured food, observers did not develop aversions to similarly coloured food. In experiment 2, we aimed to determine whether preferences for palatable food were socially learnt, and whether the extent of a demonstrators preference for novel food affected the magnitude of the observers socially learned preference. Demonstrators ate coloured food of standard or high palatability, or did not peck food at all. When the demonstrators pecked more frequently or fed more quickly from the food, the observers consumed a greater proportion of food of the same colour; however, this was only when the food was red, not green. We argue this indicates an unlearned aversion to red food, overcome by social learning of the food being highly palatable. The results provide no evidence that adult hens learn aversions through observing disgust reactions, but show that hens are sensitive to the extent of demonstrator preferences for palatable food. The data do not support the hypothesis that avian social learning is fundamentally different from that of mammals. Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.

Laboratory mice persist in gaining access to resources: a method of assessing the importance of environmental features

Abstract The welfare of caged animals can be improved by re-designing environments to include resources which are perceived by the animals as important. ‘Importance’ can be determined by increasing the cost of gaining access to resources: as the cost of access is increased, animals will persist in gaining access only to those resources which they perceive as important, i.e. gaining access will be defended. Regression equations can be calculated to describe the relationship between the cost of gaining access to resources and the rate at which gaining access disappears from the behavioural repertoire. By using traverses of shallow water in two experiments, it was determined how laboratory mice defended gaining access to feed, shelter, a conspecific or increased space (Experiment 1), and to feed, a running wheel, enrichments (‘toys’) or deep sawdust (Experiment 2). In both experiments, the mice continued to gain access to each of the resources several times each day despite having to traverse water, indicating that none of the resources was perceived as a luxury. Some resources were visited for significantly greater amounts of time, and some (different) resources were visited significantly more frequently. However, the slopes of the regression lines, i.e. the rates at which defence of visiting resources declined, were not significantly different from that for food: this can be interpreted as showing that the mice perceived defending the frequency of visits to the non-food resources to be as important as defending the frequency of visits to food, at least within the range of costs imposed in this study. These results indicate that a wide variety of resources were perceived by laboratory mice as important, and suggest that conventional designs of cage which provide only food, water, companionship and a thin layer of sawdust might be inadequate with regards to welfare.

Changes in meal patterning by mice measure the cost imposed by natural obstacles

Abstract Motivation of laboratory mice to feed was quantified by placing one of four obstacles between a home cage and a feed cage in a “closed economy” apparatus. The obstacles were an air-stream, narrow gap, shallow and deep water. Meal patterning behaviour was monitored before, during and after presentation of the obstacles. Daily food consumption was not significantly decreased by the presence of any of the obstacles. The narrow gap, shallow and deep water all significantly reduced the number of visits to the feed cage (69.4–34.0, 62.2–17.3 and 63.9 – 6.6 visits per 24 h respectively), and increased the use of an alternative return route to the home which avoided the obstacle. The shallow and deep water obstacles both significantly reduced the number of feeding bouts (22.9–19.1; 30.6–14.3 bouts per 24 h respectively) and feeding visits (18.4–12.3 and 22.3–6.2 visits per 24 h respectively). Deep water significantly increased the latency to gain access to the food (33.8–1766.4 s). Behavioural adjustments varied in a consistent manner, indicating that the responses were related, though the magnitudes of the changes were not necessarily comparable. It is argued that overcoming the narrow gap, shallow water or deep water constituted a cost to the mice, and these obstacles can therefore be used in subsequent studies to determine the elasticity of demand for resources.

Behavioural and physiological effects of absence of ultraviolet wavelengths for domestic chicks

It is increasingly clear that ultraviolet (UV) wavelengths are a component of normal avian colour perception and influence their behaviour. As artificial lighting is designed to human specifications, and so is usually deficient in UV light, there may be welfare implications for captive birds, with both context-dependent and chronic long-term effects in its absence. Domestic chicks, Gallus gallus domesticus, kept under UV-deficient environments had significantly higher basal plasma corticosterone concentrations and tended to explore less, although not significantly so, suggestive of suboptimal conditions. Chicks under full spectrum lighting had a significantly higher rate of corticosterone rise in response to capture and handling stress than chicks reared without UV, largely because a similar maximum level was reached from lower initial concentrations. These treatment differences in hormonal stress response tended to diminish with age and/or familiarity with humans, in both groups of birds.

Factors influencing floor-laying by hens in modified cages

Abstract Hens in modified cages, which incorporate nests, lay a variable proportion of eggs on the floor. This reduces the acceptability of this system as an alternative to the conventional battery cage. Observations were noted to determine if floor-laying was influenced by rearing hens in cages or on litter, by their age at transfer to the modified cages or social interactions. Cage- and litter-reared birds were obtained at 97 days of age and housed either immediately in modified cages or at 112, 129 or 145 days of age, after further time in conventional cages or on litter. Once all hens were housed in the modified cages, a 28-day observation period was conducted. Of the total eggs, 14% were laid on the floor, although the percentage of floor-eggs declined significantly during this period. A step-wise multiple regression revealed that age at transfer, rearing conditions and days since start of observations, together accounted for 40% of the variability in the percentage of floor-eggs laid per cage. Age was the most important contributory factor in the regression, with a significant positive relationship between age at transfer and percentage of floor-eggs. Litter-reared hens laid significantly more floor-eggs, made significantly more transitions in nest-site choice for reasons not obviously explicable by social interactions and made more transitions overall. These results indicate that litter-reared hens were less stable in their oviposition behaviour. During 9 consecutive days of the 28-day observation period, the majority of hens (69%) laid all their eggs in nests; a further 19% laid only 1–2 floor-eggs. Few hens used the floor consistently for laying. During the period of darkness the proportion of eggs laid on the floor was significantly greater than expected, but not during the morning or afternoon periods. The majority of hens used only one nest site; social interactions apparently influenced nest choice by others. Approximately equal numbers of the hens were gregarious or solitary in their nesting behaviour and this must be considered in future designs of modified cages.

A bespoke management package can reduce levels of injurious pecking in loose-housed laying hen flocks.

This study investigated the protective effects of an on-farm management package designed to reduce injurious pecking (IP) in loose-housed laying hens. A systematic review of scientific literature generated 46 potentially protective management strategies. Bespoke management packages were designed for treatment flocks (TF) using these management strategies. IP in 53 TFs was compared with IP in 47 control flocks (CF) where the management package was not employed. Scoring of plumage damage (PD) and observations of gentle and severe feather pecking (GFP; SFP), and vent and cannibalistic pecking (VP) were completed, and management strategy use was recorded, at 20, 30 and 40 weeks of age. Differences between treatment and CF were examined using multilevel modelling. Compared with CF, TF employed more management strategies (P<0.001), had lower PD (P=0.003) and SFP (P=0.019). Regardless of treatment or control flock status, the more of the 46 management strategies that were employed the lower was the PD (P=0.004), GFP (P=0.021), SFP (P=0.043), mortality at 40 weeks (P=0.025), and the likelihood of VP (P=0.021). Therefore, the provision of a bespoke management package was protective against the majority of forms of IP in commercial laying hen flocks.

Effects of environmental enrichment, fluorescent and intermittent lighting on injurious pecking amongst male turkey poults

1. Under commercial and experimental conditions domestic turkeys often cause injuries to pen-mates by repeated pecking, sometimes fatally. Environmental enrichment or lighting manipulations might be used to mitigate such injurious pecking. 2. This study examined responses to 4 treatments (2 rooms/treatment) of 8 groups of 100, non-beak trimmed, non-desnooded, male domestic turkeys from 1 to 35 d of age. 3. Birds of 1 treatment were reared under conditions approximating to commercial rearing (12L:12D incandescent, Control) whereas the experimental treatments were 12L:12D incandescent plus supplemental ultraviolet radiation, straw supplementation of litter, pecking substrates and visual barriers (Enriched), 12L:12D fluorescent lighting (Fluorescent), and 2(2L:3D):2L:12D incandescent (Intermittent). 4. Compared to control birds, the incidence of injuries caused by wing or tail pecking were both lower in the Enriched but not significantly different in the Fluorescent or Intermittent. 5. Injuries caused by head pecking did not occur in the Enriched rooms but were observed in at least 1 of the rooms with Control, Fluorescent and Intermittent treatments. 6. Despite considerable environmental differences between treatments, there was remarkable consistency within each type of injurious pecking in age at which injuries were 1st recorded (wing pecking, 9.38+/-1.31 d; tail pecking, 20.43+/-2.42 d; head pecking, 27.8+/-2.13 d). The roles of feather emergence, hierarchy formation in wild turkey poults and appearance of feathers are discussed as possible explanations of these consistencies.

Turkeys prefer fluorescent light with supplementary ultraviolet radiation

Turkeys are usually reared under incandescent or fluorescent lamps which emit minimal radiation in the ultraviolet region. Because turkeys have the capacity to be visually sensitive to ultraviolet radiation (UV), this possibly makes such light sources unsuited to the visual ecology of turkeys. Previous work showed that providing UV in conjunction with straw and visual barriers significantly decreased injuries due to pecking. To better understand the role of UV in behaviour and welfare, the present experiment tested the preferences of turkeys reared under fluorescent lamps either with or without an additional UV source for chambers offering fluorescent light with or without supplementary UV (N=15 turkeys/treatment; tested in groups of three). Birds of both rearing treatments chose the chamber with supplementary UV significantly more frequently than the chamber without (P=0.0001). It is concluded that the supplementary UV source was not aversive to the turkeys and that it might be considered for use in conjunction with other environmental enrichments to reduce injurious pecking.

A descriptive account of the pre-laying behaviour of hens housed individually in modified cages with nests

Abstract Incorporating nests into modified cages for laying hens might overcome some of the welfare concerns about conventional cages, though detailed behavioural studies of pre-laying in such systems must first be conducted to assess their suitability. The present study describes the pre-laying behaviour of 24 hens housed singly in modified cages, each containing two nests and compares this with pre-laying behaviour reported previously for hens in other husbandry systems. Generally, hens in the modified cages expressed a full repertoire of pre-laying activities. Displacement behaviours and pacing (usually considered as indicators of frustration) were less frequent than in conventional cages. Sleeping, sitting on the nest, nest-building behaviours and crouching were all more similar to those in extensive systems than to those observed in conventional cages. Nest entries and inspections were relatively infrequent. The modified cages appeared to be more acceptable on welfare grounds than conventional cages without nests, however, the abnormal behaviour of some hens indicated considerable individual differences existed which must be considered in future designs.