Farm Animals

Farm Animal: Pig Aggression at Regrouping Welfare

Regrouping of pigs at weaning, mixing and introduction stages causes severe aggression as hierarchies are established, representing a significant welfare challenge.

Key Facts

Pigs establish dominance hierarchies through fighting when unfamiliar individuals meet
Regrouping aggression causes skin wounds, stress and exhaustion in affected animals
Mixing of unfamiliar pigs is common practice at weaning and between production stages
Reduced stocking density and provision of hiding places reduce severity of mixing aggression
Olfactory familiarisation before physical mixing can reduce aggression intensity

Welfare Considerations

Regrouping aggression is a welfare problem inherent in the practice of mixing pigs from different social groups. The pain and stress of fighting can be reduced but not eliminated by management. Stable social groups maintained throughout production cycles would largely eliminate this welfare harm.

What You Can Do

Support pig welfare standards requiring stable group maintenance where possible
Advocate for adequate space and hiding places during unavoidable mixing events
Choose pork from systems with documented lower aggression management
Fund research into olfactory and other pre-mixing familiarisation techniques