Pigs establish stable social hierarchies that reduce aggression and stress, but commercial farming practices that mix unfamiliar pigs frequently disrupt these structures.
In their natural social structure, pigs live in stable matrilineal groups with established hierarchies that minimize the need for constant conflict. Commercial systems that repeatedly mix pigs at weaning, regrouping, and transport force animals into repeated high-stress fighting to re-establish dominance. These bouts cause physical injuries and chronic stress. Maintaining stable social groups throughout the production cycle is one of the most impactful welfare improvements available.