Pig Farming

Pig Aggression at Regrouping and Intervention

Regrouping aggression in pigs causes injuries and stress that can be reduced through evidence-based management strategies.

Key Facts

Pigs establish social hierarchies through aggression when unfamiliar animals are mixed
Regrouping injuries include bite wounds, scratches, and in severe cases death
Regrouping in neutral pens with escape routes reduces injury severity
Application of masking agents reduces olfactory-based aggression when pigs are mixed
Providing straw and toys at mixing distracts pigs and reduces aggressive encounters

Welfare Considerations

Regrouping is unavoidable in many pig production systems, but its welfare cost can be significantly reduced. Providing enrichment at mixing, using neutral pens, allowing escape from aggression, and minimising the number of mixing events across the production cycle all reduce suffering. Stockpeople skilled in recognising and managing regrouping aggression can intervene before injuries become severe.

What You Can Do

Support pig welfare certification preferring systems minimising regrouping events
Advocate for enrichment provision at mixing as a welfare standard
Choose pork from farms with documented low regrouping injury rates