Behaviour, wounds, weight loss and adrenal weight of rabbit does as affected by semi-group housing

•We compared rabbit does in semi-group housing to rabbit does in single-doe housing.•Semi-group does spent a greater % of time on locomotion and social behaviour.•This suggests welfare advantages but differences were small and decreased over time.•Adrenal weight and weight loss were not influenced favourably by semi-group housing.•Wounding was common in semi-groups, impacting negatively on welfare. Group housing is often assumed to improve the welfare of gregarious species. Whether this is actually the case depends on the advantages (e.g. more opportunity for social and locomotor behaviour) and disadvantages (e.g. increased fighting and wounding) induced by the specific housing type. We evaluated the effects of a semi-group system (grouping four does for half of each reproductive cycle) on welfare by comparing it to single-doe cages. Compared to this control, our semi-group system provided more total space when does were grouped and more space per doe (a confounding deemed necessary to avoid overt aggression). Thus, the results should be interpreted as a systems comparison. In each of the four experimental cycles semi-group does were housed separately for 21 days around parturition and housed in newly assembled groups for the next 21 days. Behaviour was observed in semi-group and single-doe systems immediately after the second time semi-group does were mixed, and during five timeslots divided over the second experimental cycle. Skin lesion and weight loss were determined in each cycle. Adrenal weight was measured post-mortem. Semi-group systems with different floor types were included but floor type effects were scarce and semi-group systems were therefore treated as one category. In the timeslot subsequent to mixing semi-group does spent a greater percentage of their time on locomotion (4.3 vs. 0.7%, P