| Despite being highly social under natural conditions, laboratory rabbits are often housed individually, and show higher levels of abnormal behavior than socially-housed rabbits. I conducted three studies to determine how social or physical enrichments affected the behavior of individually- or pair-housed rabbits, to subsequently determine the type of enrichment from which rabbits would benefit. Rabbits remained in their assigned housing treatment through all studies. In the first study female rabbits were housed individually in single cages (61 x 76 x 41) or in non-littermate pairs in double-wide cages (122 x 76 x 41). Individual rabbits developed more abnormal behaviors like stereotyped digging, bar biting, and floor chewing than paired rabbits. Aggression in paired rabbits was generally low and stable across the study, although one pair was separated due to persistent bite wounds. For the second study, rabbits were moved to large floor pens (2.44 x 1.22 x 0.61m), and their use of four species-appropriate enrichment objects, a nestbox, tunnel, haycubes, and Bunny Blocks, was characterized. Rabbits used the nestbox significantly more than the other three items. In a series of comparisons, I assessed whether behavior or enrichment use was affected by rearing (individual or paired), the presence of a pairmate (pairs housed individually or together), and the social status of paired rabbits. Rearing had no effect, while paired rabbits tended to dig and use the nestbox more when housed alone. Social status influenced behavior, but not enrichment use. In the third study, to measure the rabbits' motivation, I conducted a consumer demand preference test, during which rabbits were required to push through weighted doors to gain access to various resources (familiar and unfamiliar conspecifics, food, or enrichments in the form of a nestbox and tunnel). Paired rabbits significantly preferred food and the unfamiliar conspecific to the other resources while individual rabbits showed no preference among the non-food resources. These studies indicate that paired rabbits, at least, are more motivated to access social than physical enrichment, which is successful in reducing abnormal behaviors, an indicator or poor welfare, in caged rabbits. If pair-housing cannot be accommodated, physical enrichments based upon characteristics of the nestbox may help improve the housing of laboratory rabbits. |
