Farm Animal Welfare

Pig Social Hierarchy Stress Management

Establishing social hierarchies in newly regrouped pigs causes significant aggression, injury, and chronic stress for subordinate individuals. Management strategies can reduce the welfare cost of regrouping.

Key Facts

Pigs fight intensively for 24-48 hours when new social groups are formed
Injuries from fighting include skin wounds, ear damage, and occasionally fatal attacks
Regrouping is a major welfare challenge because commercial production moves pigs between groups frequently
Providing straw, dim lighting, and increased space reduces fighting at regrouping
Pheromone sprays and olfactory masking reduce fighting in some studies

Welfare Considerations

The repeated social disruption of commercial pig production creates recurring cycles of aggression and stress that subordinate animals particularly suffer from. Each regrouping event involves injury risk and social uncertainty for every animal in the group. Minimising regrouping frequency and optimising conditions when regrouping is unavoidable are important welfare priorities.

What You Can Do

Support pig welfare standards that specify minimum conditions for regrouping
Advocate for production systems that minimise group changes throughout production
Choose pork from farms committed to stable social group management