Pig Social Behaviour: Why Group Housing Matters for Welfare

Pigs are highly social animals with complex group dynamics. Understanding their social behaviour is essential for designing housing systems that meet their welfare needs.

Key Facts

Wild and feral pigs live in stable social groups of related females (sounders) and their offspring
Pigs establish social hierarchies through agonistic interactions — these are normal but can cause welfare problems when management creates instability
Regrouping unfamiliar pigs causes intense fighting until a new hierarchy is established — a significant welfare event
Stable groups with space for subordinate animals to avoid dominant individuals reduce chronic aggression
Positive social behaviours including play, social investigation, and lying in contact with companions are welfare indicators
Group housing is required in the EU but space allowances and management quality vary significantly

Welfare Considerations

Pig social behaviour is simultaneously a welfare opportunity and a welfare risk. When social groups are stable, appropriately sized, and housed with enough space, social behaviour is a source of enrichment and positive interaction. When groups are frequently disrupted by regrouping, when space is insufficient for lower-ranking animals to escape dominant pigs, or when resources are concentrated, social behaviour becomes a source of injury and chronic stress. Welfare-centred pig management minimises regrouping events, provides sufficient space and resources for all animals, and monitors outcomes through observation of social behaviour quality.

What You Can Do

Support farms that minimise regrouping and maintain stable pig social groups throughout production
Choose pork products from farms with space allowances above legal minimum — more space reduces social stress
Advocate for regrouping protocols that include analgesic pre-treatment during unavoidable mixing events
Support research into housing designs that reduce aggression during unavoidable regrouping
Engage retailers to require suppliers to report regrouping frequency as a welfare indicator