Effect of hiding places, straw and territory on aggression in group-housed rabbit does

Group-housing of rabbit does may be preferred from welfare point of view. However, group-housing causes agonistic behaviour which may cause severe injuries. Severe injuries may be prevented by offering hiding places for attacked does. Providing enrichment (straw) may reduce agonistic behaviour by attracting attention from fighting. In contrast, acquisition of a territory within a group may evoke aggression. An experiment was conducted in which the effect of hiding places, straw and territory on aggression in intermittent group-housed rabbit does was studied. The group-housing system consisted of four adjacent enriched individual cages that had been transformed into one group pen for four does by taking out three side walls. Group pens were 1.0 m × 1.5 m × 0.6 m (length × width × height). Does were housed individually until 18 days of lactation. As of day 18 of lactation, four multiparous hybrid does (Hycole) with their kits were housed in a group until 35 days of lactation. All combinations of the following factors were randomly assigned: hiding places (platform and PVC pipe), straw and territory (i.e. familiarity with the cage before grouping) (8 treatments). Sixteen pens were used during 5 successive lactations of 35 days (n = 10/treatment). Behavioural observations were performed at two afternoons at the start and end of the group-housing period of each lactation and skin injuries were registered on 4, 7, 10, 14 and 17 days after being group-housed. Does were resting 70% of the observed time. Does with territory showed significantly more comfort behaviour than does without territory (13% vs. 9% of the observed time, respectively; P < 0.05). At start does showed less comfort behaviour and more locomotion than at the end of the group-housing period (7% vs. 15% and 2% vs. 1% of the observed time, respectively; P < 0.05). Occupation with straw, stereotyped behaviour and fights were only observed in 4%, 3% and 0.3% of the does, respectively. There were no differences in skin injuries between treatments. Overall 52% of the does had injuries. The percentage of does that had severe injuries ranged between 13% and 39%. Treatments with hiding places had the lowest numerical percentage of severe injuries and there was a tendency (P < 0.1) for less culled does in this treatment. In conclusion, does do not defend a territory within a group pen. Hiding places can help to reduce severe skin injuries. However, the high amount of does with skin injuries merits further study.