Farm Animal Welfare

Pig Welfare and Aggression at Regrouping

Regrouping unfamiliar pigs triggers intense aggression to establish dominance hierarchies. The resulting injuries and chronic stress represent a major welfare challenge in commercial pig production.

Key Facts

Pigs typically fight for 24-48 hours when regrouped with unfamiliar individuals
Bite wounds from fighting can become infected and require veterinary treatment
Smaller and lighter pigs suffer disproportionately in mixed-weight groups
Deep litter and refuge areas allow subordinate pigs to avoid dominant individuals
Olfactory masking sprays with limited effectiveness are commercially available

Welfare Considerations

Regrouping aggression is a persistent welfare problem in systems that mix unfamiliar pigs. Strategies including stable group management, early mixing and environmental design can significantly reduce its impact.

What You Can Do

Advocate for stable group management policies in pig welfare standards
Support research into effective, humane methods to reduce mixing aggression
Choose pork from farms audited for minimising regrouping stress