Tail biting in pigs is a welfare emergency that causes serious injury and is a symptom of inadequate management; a systems approach addressing nutrition, enrichment, and stocking is more effective than mutilation.
A tail-biting outbreak is one of the most dramatic indicators of welfare failure in a pig unit. Pigs are intensely motivated to investigate and manipulate objects; when deprived of appropriate outlets, they direct this behaviour toward the tails of pen mates. Once started, the behaviour escalates rapidly as the smell of blood attracts additional biting. Injury is severe: wounds penetrate to the vertebrae in serious cases and become infected. The appropriate response is to address root causes — enrichment provision, stocking density, ventilation, and nutrition — rather than simply docking tails as a preventive mutilation.