Farm Animal Welfare

Pig Group Housing: Aggression Management at Introduction

Evidence-based strategies for reducing aggression when pigs are mixed into new groups.

Key Facts

Mixing unfamiliar pigs causes immediate and intense aggression as a new hierarchy is established
Injuries during mixing include skin lacerations, ear damage, and occasional serious wounds
Temporary use of aggression-reducing sprays (e.g. synthetic androstenone) shows mixed efficacy
Providing multiple escape routes, visual barriers, and abundant resources reduces injury rates

Welfare Considerations

The acute welfare impact of pig mixing is significant and often avoidable. Stable group management - minimising unnecessary mixing and providing appropriate housing when mixing is unavoidable - is one of the most impactful welfare improvements available in commercial pig production.

What You Can Do

Support welfare standards that require stable group management from weaning to slaughter
Advocate for housing specifications that include visual barriers and escape routes for mixed groups
Choose pork from producers with documented mixing protocols and injury monitoring