Run access, hutch size and time-of-day affect welfare-relevant behaviour and faecal corticosterone in pair-housed pet rabbits

Although there exist several studies examining the housing needs of rabbits kept in laboratories and for meat, studies of the requirements of pet rabbits are few and focus entirely on single rabbits. Pet rabbits are recommended to be kept in pairs. We therefore conducted an experimental study to investigate the effects of common hutch sizes and access to an exercise area on the welfare of pairs of pet rabbits. Twenty pre-established pairs of adult neutered rabbits (one male, one female) were kept for eight weeks in standardised housing, Ten pairs were in small wooden hutches (0.73 m2) and ten in large (1.86 m2). An exercise area measuring 3x1 m was attached to each hutch and access was either unlimited or restricted to 3 h in the middle of the day. Each pair experienced each run access for three weeks in a counterbalanced design. We sampled behaviour at dawn, dusk and midday, and took faecal samples for corticosterone analysis at the end of each access treatment period. In a subsequent study, ten of the rabbit pairs were given 24 h access to the run, and their behaviour recorded. More overall time was spent in locomotion when run access was restricted to 3 h (F 1,17 =5.26, p = 0.035). Regardless of size of hutch, locomotory activity including play increased significantly when the pairs with restricted access were released into the run. This indicates a motivational rebound after behavioural restriction demonstrating the rabbits' need to move within each 24 h cycle, as well as improved welfare There was a significant interaction between hutch size and run access on corticosterone levels; they were raised in the pairs kept in small hutches with restricted run access (F1,17 = 4.58, p = 0.047). The mid-day period was found to be their least active. Restricting rabbits' opportunity to move and to get away from each other to times of day, when they would not naturally be as active, is likely to have contributed to the raised stress hormone levels in the pairs in the smaller hutches. Housing guidelines thus need to highlight the importance of allowing pet rabbits the freedom to exercise outside the mid-day period, even if they are kept in hutches larger than common practice. Hutches of commonly reported sizes of around 0.75 m2 floor area should not be recommended for rabbit pairs, even with access to an exercise area for three hours per day during the middle of the day.

Automated summary

Although studies on the housing needs of laboratory and meat rabbits are available, there is a lack of research on the requirements of pet rabbits, particularly those kept in pairs. This study found that small hutches and restricted access to an exercise area can lead to increased stress hormone levels in pet rabbits, highlighting the importance of providing rabbits with sufficient exercise freedom.