Semi-group housing - do commercial breeding rabbits benefit from the presumed advantages?

Group housing of rabbit does (the mothers of meat rabbits) has been suggested to improve welfare by increasing possibilities for positive social interactions and locomotion. However, it is unknown whether does actually take advantage of such opportunities. We compared the time-budget of does housed in 8 semi-group systems (4 does + litters housed together per system between 18 and 30 days post-partum) and 16 single-doe cages (1 doe + litter/cage). Does were observed at daytime and night-time on the day of grouping (“D1”, “N1”) and 4 and 12 days thereafter. Treatment differences were evaluated within time period using Kruskal-Wallis tests. During D1 hopping was more common in semi-group systems than in single-doe cages (P≤0.01, semi-group: 4.3%(3.8-5.0), single-doe: 0.7%(0.6-0.8)). A similar effect was found for hopping during all nights, although treatment differences were small (2.6, 1.8 and 0.6% for N1, N4 and N12, respectively, P<0.05). Social sniffing/allogrooming (the latter being very rare and never reciprocal) took up <2% of the time in semi-group systems during all time periods. It was absent in single-doe cages, although theoretically possible due to wire cage walls. Surprisingly, bodily contact between does was more common in single-doe cages than in semi-group systems during D1 and N1 (P<0.01, D1: 12(11-15) vs. 1.6%(0.7-3.1), N1:11(8.9-14.0) vs. 0.6%(0-3.0)) and did not differ between systems afterwards (P>0.10). In semi-group systems agonistic behaviour took up 7.0%(6.3-9.5) of the time during D1 but declined to 0.7%(0.3-1.7) on N1 and remained below 0.3% afterwards. Agonistic behaviour was absent in single-doe cages. In summary, the limited differences in the time-budget provide little evidence that rabbit does actually benefit from the increased total space allowance and social options offered by our semi-group system. However, even small changes can be valued highly and further research is needed to elucidate how important these differences are to rabbit does.