Farm Animal Welfare

Pig Aggression Management - Review of Interventions

A comprehensive review of strategies to reduce aggression in pigs, covering group composition, environmental enrichment, and management timing.

Key Facts

Regrouping unfamiliar pigs triggers acute aggression lasting 24-72 hours with welfare and production consequences
Providing rooting substrate like straw reduces aggression frequency by up to 40% in multiple studies
Single-sex groups show less sustained aggression than mixed-sex groups post-weaning
Olfactory familiarization before physical mixing significantly reduces fighting duration
Space allowance below recommended minimums correlates strongly with increased aggression rates

Welfare Considerations

Pig aggression causes physical injury, psychological stress, and suppressed immune function. Chronic subordinate pigs experience persistent stress responses affecting growth and health. Interventions that reduce aggression frequency and severity meaningfully improve welfare across the entire group, not just for individual animals.

What You Can Do

Implement straw-based bedding or rooting enrichment to reduce redirected aggression
Allow olfactory familiarization by pen-swapping bedding before physical mixing
Ensure space allowances meet or exceed minimum regulatory requirements
Time regrouping to early morning when pigs are less active and supervision is possible
Monitor and record aggression events to evaluate intervention effectiveness