Farm Animal Cognition

Emotional Contagion in Domestic Pigs

Pigs can catch emotions from their pen-mates, a finding with significant implications for group housing welfare in commercial farming.

Key Facts

Research shows pigs exposed to stressed companions show elevated cortisol and behavioral anxiety
Pigs raised in positive social environments transmit optimistic cognitive bias to pen-mates
Emotional contagion in pigs extends to strangers, not just familiar individuals
Commercial pig housing often mixes unfamiliar animals, creating chronic social stress
The capacity for emotional contagion indicates empathy-like processes in pigs

Welfare Considerations

Emotional contagion means welfare harms can propagate through a group — one fearful or injured pig can induce stress in pen-mates. This argues strongly for both minimizing individual aversive events and ensuring positive social bonds are preserved within stable groups.

What You Can Do

Support farm certifications requiring stable social groups and no unnecessary mixing
Reduce or eliminate pork consumption from systems with barren group housing
Advocate for farm animal welfare science to inform commercial pig husbandry standards