Pig social dynamics including dominance hierarchies, agonistic behaviour, and social bonding significantly affect welfare; management practices that respect social needs improve outcomes.
Pig social welfare is shaped by the interaction between natural social tendencies and commercial management requirements. Pigs have evolved complex social structures with stable hierarchies that minimise ongoing aggression once established; the management practice of frequent group mixing for production purposes repeatedly disrupts these structures and resets fighting. Small, stable social groups that maintain consistent membership throughout the production cycle achieve the best social welfare outcomes. The practical challenge is that commercial production systems optimised for efficient pen use involve regular regrouping. Management protocols that minimise mixing — through all-in all-out production by pen or farm section — provide better social welfare with achievable production changes.