Pig Social Behaviour and Group Management

Pigs are highly social animals with complex social hierarchies that are disrupted by commercial mixing practices, causing welfare harm through fighting and stress.

Key Facts

Pigs establish stable linear dominance hierarchies within groups
Mixing unfamiliar pigs causes severe fighting that can result in injury and death
Post-mixing stress elevates cortisol for 24-72 hours
Stable long-term groups show markedly less aggression than repeatedly mixed groups
Boars are particularly vulnerable to mixing-induced aggression

Welfare Considerations

Commercial pig production routinely mixes pigs at weaning, after vaccination, and before slaughter for production management reasons. Each mixing event triggers a period of fighting as animals establish a new hierarchy. This causes injuries, stress, and disruption of feeding and resting patterns. Minimising mixing events through stable group management significantly reduces this welfare harm. Systems that maintain birth groups throughout production substantially improve social welfare.

What You Can Do

Support welfare certification that limits or prohibits unnecessary pig mixing
Advocate for stable group management requirements in pig welfare legislation
Choose pork from farms with documented mixing reduction practices
Back research into management systems that maintain stable social groups
Support farmer education on mixing reduction strategies and their economic benefits