It has been suggested that housing of laboratory primates in two-tiered racks adversely affects the psychological well-being of those primates housed on the lower row. Excessive darkness and its consequences are among the factors suggested to account for the supposed diminished well-being of lower-row inhabitants. Additionally, two-tiered housing has been suggested to introduce unacceptable variation into experimental designs, potentially necessitating additional subjects and/or invalidating results. Only recently have data been published to address these issues, but all studies have involved small numbers of subjects. In the present study, we compared the behaviour of 45 yearling rhesus macaques (Macaca mulatta) housed in upper-row cages with the behaviour of 48 yearling rhesus macaques housed in lower-row cages during a year of single housing. There were no significant differences across cage locations for time spent performing behaviours indicative of diminished psychological well-being (abnormal behaviour, inactivity, vocalisation, self-directed grooming) or for species-typical activities (feeding, playing). The difference in time spent exploring between macaques housed on the lower row and those housed on the upper row approached significance, with lower-row-housed animals spending more time exploring. Although lower-row cages are significantly darker than upper-row cages at our facility, the data from the present study demonstrate that the diminished lighting and other supposed disadvantages experienced by lower-row-housed monkeys have few behavioural consequences. Thus, there are now additional empirical data that suggest that lower-row-housed monkeys are not suffering in a “monkey cave”, and that the findings of research projects using two-tiered housing systems are unlikely to be compromised.

An increasing public concern over the welfare of livestock species is motivating more producers to consider changes to production practices. Providing environmental enrichment for intensively housed animals is one such potentially welfare-enhancing change. The goal of environmental enrichment is to provide biologically relevant environmental stimuli that allows an animal to perform highly motivated, species-specific behaviours. To date, there is no research specific to the applicability of environmental enrichment for commercial boars (Sus scrofa domesticus), nor on commercial boar welfare in general. In this study, eight individually housed, mature boars were observed to prefer interacting with hanging cotton rope enrichment over hanging rubber chew sticks when given the option. There was a significantly negative correlation between the amount of time boars spent interacting with rope and the amount of time they spent performing stereotypic pen manipulation, suggesting that the rope was more effective at reducing stereotypic behaviour than the rubber. Such reductions in amount of time spent performing abnormal stereotypic behaviours could indicate that some of the animals’ behavioural needs are being met by the enrichment object. Thus, the results of this study could help provide producers with more objective, research-based suggestions concerning the efficacy of practical enrichment choices for individually housed boars.

Positive reinforcement training is one component of behavioural management employed to improve psychological well-being. There has been regulatory promotion to compensate for restricted social housing in part by providing human interaction to singly caged primates, implying an efficacy standard for evaluating human interaction. The effect of positive reinforcement training on the behaviour of 61 singly housed laboratory rhesus macaques (Macaca mulatta) was evaluated at two large primate facilities. Training involved body part presentation and basic control behaviours. Baseline data were compared to two treatment phases presented in varying order across individuals, six minutes per week of positive reinforcement training and six minutes per week of unstructured human interaction. While a MANOVA involving behavioural categories and study conditions across study subjects was significant, univariate ANOVAs found no effect of phase within any behavioural category. Categorising subjects according to rearing, housing facility, or baseline levels of abnormal behaviour did not reveal changes in behaviour with positive reinforcement training or human interaction. This study failed to detect, to any degree, the types of behavioural changes documented in the scientific literature to result from pairing singly housed monkeys. Implementing short durations of positive reinforcement training across large numbers of singly housed animals may not be the most effective manner for incorporating positive reinforcement training in the behavioural management of laboratory macaques. Rather, directing efforts toward individuals with specific behavioural, management, clinical, research or therapeutic needs may represent a more fruitful approach to improving psychological well-being with this technique.

Although rabbit does are generally single housed on rabbit farms worldwide, it has been suggested by some specialists and recommendation of organic rabbit production systems that group housing of does is more comfortable and similar to the living conditions of the European wild rabbits. The aim of this experiment was to compare production of single-caged (S) and group-housed does (G). The S does were housed in commercial rabbit cages (floor area 0.32 m2 and 0.3 m high). In treatment G, four does and one buck were housed in four pens measuring 7.7 m2 (half of the floor was deep litter and the other half was plastic slat), with four nest boxes in each pen (n = 16). In treatment S, approximately half of the does (n = 18) were inseminated 2 days after kindling (S-33), whereas in the remaining does (n = 16) AI was done 11 days after kindling (S-42). A single-batch system (all of the does in the group were inseminated on the same day) was used in both S treatments. Kindling rates were 77.6%, 85.2% and 45.6% in treatments S-33, S-42 and G, respectively (P < 0.05). During the experiment, the percentage of does that kindled 0, 1, 2, 3, 4 and 5 times were 17%, 25%, 17%, 25%, 17% and 0% (G); 0%, 0%, 0%, 8%, 69% and 23% (S-33); and 0%, 0%, 17%, 58% and 25% (S-42, in this treatment does had a maximum of four kindlings). There were no significant differences among treatments for litter size. In treatments S-33, S-42 and G, suckling mortality was 14.0%, 15.2% and 38.5%, respectively (P < 0.001); survival of does was 71%, 81% and 50% (P = 0.084); and faecal corticosterone concentrations were 61, 54 and 175 nmol/g (P < 0.001). The high mortality of kits was associated with stress and aggressive behaviour of does, including scratching, biting or killing the kits, which resulted in the high rates of mortality and culling, as well as shorter lifespan of does. Because of high stress, increased mortality and morbidity, and low productivity, group housing of rabbit does resulted in poorer animal welfare and increased production costs, and therefore is not recommended.