Livestock

Livestock Pig Group Size and Social Welfare

The size of pig social groups affects their welfare through social stability and aggression dynamics.

Key Facts

Large groups of pigs experience more instability and mixing than small groups
Familiar pigs form stable hierarchies with less ongoing aggression
Larger groups make it harder to maintain stable social relationships
Small group housing with stable memberships reduces chronic stress

Welfare Considerations

Pigs repeatedly mixed with unfamiliar animals experience ongoing aggression as new hierarchies are established. Each mixing event causes acute fear, injury risk, and physiological stress. Systems that maintain stable social groups throughout production — avoiding mixing except where absolutely necessary — reduce chronic social stress significantly. Group size should be manageable for the social complexity of the species.

What You Can Do

Support pig production systems that maintain stable social groups
Advocate for mixing standards that minimise unnecessary regrouping
Choose pork from producers with documented social group management
Back research into optimal group sizes and composition for pig welfare