Pigs have complex social structures that commercial housing disrupts - understanding pig social behaviour enables management that reduces aggression and improves welfare.
Pig social behaviour is sophisticated and welfare-relevant. Regrouping - mixing unfamiliar pigs of different sizes and social backgrounds - causes predictable intense aggression. The welfare-positive response is to minimise mixing events, use small groups when mixing is unavoidable, provide adequate space and retreat options, and monitor until social stability is established. Producers who understand pig social behaviour and design management systems around it achieve lower injury rates and better overall welfare.