The impact of behavioural disorders on animal welfare in modern animal husbandry has been much debated. While other abnormal behaviours have been explored at length, there are a paucity of studies on tail-biting in rabbits (Oryctolagus cuniculus). In the present study, severe tail lesions were observed in group-reared rabbit does on a commercial rabbit farm. In the subsequent investigations, the occurrence of tail lesions in 219 rabbit does from nine batches was compared between group- or singlehousing and a scoring system recording the severity of tail lesions was developed and verified. This five-grade scoring system was applied to evaluate the progression of prevalence and severity of tail lesions in 21 groups during rearing in two batches. The results revealed a significant difference in the score level between housing types with a higher prevalence of injured tails in group- (60.4%) compared to single-reared (4.0%) does. An increase in severity and frequency of tail lesions was observed in groups during the course of a rearing period. Furthermore, the established scoring system was characterised by adequate observer reliability. Overall, tail injuries occurred on a regular basis in the investigated rearing groups, indicating tail-biting to be a prevalent problem. This could be considered relevant in terms of animal welfare, both for the animal doing the biting and the individual being bitten. The findings draw attention to an inadequately described problem in rabbit husbandry. However, the search for preventive measures needs to scrutinise the role of single-housing, without failing to consider the gregarious nature of rabbits.
