Farm Pig Aggression Management and Injury Prevention

Aggression between pigs causes significant injuries and welfare problems in intensive systems, and managing the root causes rather than treating symptoms is essential for meaningful welfare improvement.

Key Facts

Mixing unfamiliar pigs triggers intense aggression as dominance hierarchies are re-established through fighting
Skin lesions from fighting affect a significant proportion of pigs in intensive systems
Aggression accounts for a major portion of pig injury and mortality in commercial production
Stable social groups with consistent membership show dramatically lower aggression than frequently mixed groups
Adequate space, multiple feeding points, and enrichment all reduce aggression in pig groups
Some producers use water spraying or partitions during mixing to reduce initial aggression severity
Breeding selection for lower aggression reactivity is an emerging welfare improvement approach

Welfare Considerations

Pig aggression in intensive systems is not a natural inevitability — it is a predictable consequence of management practices including frequent social mixing, inadequate space, and resource competition. Stable social groups that are not disrupted by routine mixing show far lower injury rates. The industry practice of mixing pigs at weaning, transfer, and regrouping imposes repeated acute stress as hierarchies are violently re-established. Each mixing event causes injuries that cause pain, impair feeding, and create chronic welfare deficits. Preventing aggression through stable social management is achievable and reduces the veterinary costs associated with injury treatment.

What You Can Do

Support welfare standards requiring stable social group management and limits on mixing frequency
Advocate for regulations requiring minimum space and feeding point standards that reduce competition
Choose pork from certified higher-welfare producers with stable social group management
Reduce or eliminate pork consumption to decrease demand from high-aggression systems
Support research into pig breeding for lower aggression and better social compatibility
Urge food companies to require aggression and injury rate monitoring from their pork producers