Farm Animal Welfare

Pig Aggression at Regrouping and Mixing

Mixing unfamiliar pigs causes intense fighting that can last hours and result in injuries, distress and deaths.

Key Facts

Pigs establish dominance hierarchies through fighting when mixed
Post-mixing fights can last 24-48 hours with serious injury risk
Mixing pigs at weaning, transfer and regrouping are the highest-risk events
Strategies like mixing in neutral spaces, large group housing and sedation reduce aggression
Providing hiding spaces and visual barriers reduces fight severity

Welfare Considerations

The welfare cost of mixing and regrouping is substantial, with acute pain from bites and sustained stress during hierarchy establishment. Management strategies that minimise mixing frequency and severity are among the most welfare-positive changes available.

What You Can Do

Support producers using large group housing that minimises regrouping frequency
Advocate for research into effective low-stress mixing strategies
Choose pork from farms with enriched group housing reducing mixing stress