Animals can communicate with one another through various types of signals. Evidence is presented that in certain experiments with rats, stress as induced by experimental treatment may give rise to the production of signals that affect non-treated animals housed nearby. Such communication between test and control animals may cause biased results and disturbed welfare of the latter. Communication of stress may be prevented by separate housing of control and test animals, but this could introduce another source of bias.

The use of woodchips as bedding for 16 juvenile chimpanzees (Pan troglodytes) was evaluated for the effects on behaviour, health and husbandry practices. Woodchip bedding was placed in two outdoor play areas for five consecutive days. Behavioural data were recorded in the morning and afternoon of each day, and compared to pre- and post-test data. A total of 44 hours of observations, made up of 1 hour scan sample sessions, were completed for the study. Behaviours in the following categories were measured: abnormal, affinitive, aggressive, environmental manipulation, inactivity, locomotion, play, self manipulation and woodchip manipulation. The location of each animal was also recorded Analysis of the data indicated that the chimpanzees engaged in woodchip-related behaviours for an average of 20.52 per cent of the data points, and that they spent more time manipulating the substrate in the morning than in the afternoon. In addition, abnormal behaviour, environmental manipulation and affinitive behaviours were significantly lower during the woodchip condition than during pre-test and post-test conditions. The subjects spent the most time on the floor of the enclosure, and this measure did not differ between conditions. The woodchip bedding did not cause any known health problems for the chimpanzees. Although the daily addition and removal of woodchips took more time than did routine cleaning, it kept the play areas cleaner and drier. The evaluation of woodchip bedding as enrichment was favourable and indicated that bedding may be used regularly in the maintenance of captive chimpanzees.

Every year sees an increase in the number of dogs admitted to rescue shelters. However well these dogs are cared for in the shelter it cannot be ignored that being in such a situation is stressful, and the time spent in the shelter may change the dogs’ behaviour which may in turn influence their chances of being bought from the shelter. This research examined the behaviour of stray and unwanted dogs on their first, third and fifth days in an Ulster Society for the Prevention of Cruelty to Animals (USPCA) shelter. A questionnaire was also distributed to members of the public to determine how popular the USPCA was as a place from where to purchase a dog, and what factors about a dog's physical characteristics, behaviour and environment influenced potential buyers. Results revealed no significant difference between the behaviour of stray and unwanted dogs although the public viewed stray dogs as much less desirable than unwanted dogs. Time in the shelter had no adverse effects on the dogs’ behaviour. Indeed those changes which did occur during captivity, dogs being more relaxed in the presence of people and eating food more quickly, may be considered as positive changes. The USPCA was viewed as a popular place from which to buy a dog. Of factors influencing the public's choice, the dog's environment and behaviour appeared more important than its physical characteristics. The presence of a toy in the dog's cage greatly increased the public's preference for the dog, although the toy was ignored by the dog. The welfare implications of sheltering dogs are discussed.

Dustbathing in fowls (eg chickens, Gallus gallus) consists of tossing the litter onto and between the fluffed feathers and subsequently enclosing it by flattening the feathers. The proximal contact between litters like sand and peat, and the integument is intensified by rubbing the body. This is not the case in wood-shavings which adhere to the distal plumage after tossing; rubbings in wood-shavings are frequently interrupted by reinitiated tossings. Lipids accumulate on the feathers and become stale during dust deprivation. Only baths in sand and peat are effective in removing excessive lipids from the proximal downy feather parts. Fluffiness of the down is highest in hens on peat, intermediate on sand and lowest on wood-shavings, while the reverse is true for the plumage surface temperature of the back Hens monitor the integumental lipid condition which becomes causally connected with bathing in the course of experiencing litter bathing effects. It is shown from the author's experimental study that hens naive of bathing in litter, and hens experienced with wood-shavings initially shifted bathing litters but finally preferred peat or sand (in that order) when peat, sand and wood-shavings were simultaneously presented Most of the hens experienced with bathing in sand did not shift to another substrate when presented with one. Recommendations are given concerning adequate dustbathing litter. A chronic deprivation of adequate litter leads to an uncontrollable condition of the lipids on the integument and an abnormal development of dustbathing. Such a deprivation therefore reduces animal welfare. Moreover, it is suggested to be costly.

Mammals are unique among vertebrates in experiencing a need to carry out behaviours which are not necessary for their immediate survival. This poses questions as to the nature of these behavioural needs, how they evolved and their implications for the welfare of mammals in captivity. Evidence is provided to show that mammals carry out daily programmes of activity which meet four kinds of requirement, namely, for security, appropriate environmental complexity, novelty and opportunities for achievement. Within their programmes mammals perform two kinds of activity: work, which relates to day to day survival, and leisure, in the form of curiosity or play, which provides experience which may prove to be of value in the long term.

The existence of behavioural needs is consistent with our knowledge of mammalian evolution. Even the earliest known mammals, living over 120 million years ago, differed from reptiles in having brain to body size ratios four to five times greater. The increase in brain size resulted largely from the massive expansion of a region of the cerebral cortex, known as the neopallium, which acts as a co-ordinating centre for sensory data, and creates a model of the world which determines subsequent action. During the 60 million year tertiary era, relative brain size increased in most orders of eutherian mammals, so that only the more intelligent survived.

Because mammals rely for their survival on collecting and analyzing data and acting intelligently, they need facilities to search for information to establish and monitor their concept of the real world; their psychological well-being depends on an environment which offers such facilities. There are two kinds of behavioural needs; psychological needs, which appear to be unique to mammals, and ethological needs which are experienced by all vertebrates. It is concluded that environmental quality for captive mammals should not just be assessed negatively, by the absence of abnormal behaviours, but more positively by the extent to which it meets their psychological needs.