Positive Affect in Pigs: Measuring and Promoting Good Welfare

Welfare science increasingly focuses not just on preventing suffering but on promoting positive emotional states in pigs — an approach with practical implications for farming.

Key Facts

Pigs show optimistic cognitive bias — positive interpretation of ambiguous stimuli — when housed in enriched, stimulating environments
Play behaviour in pigs correlates with lower cortisol, higher serotonin and positive limbic system activity on brain imaging
The Qualitative Behaviour Assessment tool allows trained observers to reliably rate positive emotional states including relaxation and curiosity in pig groups
Pigs in enriched environments spend more time in active exploration, play and social engagement than pigs in barren systems
Positive human-animal interactions — gentle handling, talking to pigs — produce measurable improvements in welfare indicators and handling ease
The Five Domains model of animal welfare explicitly includes positive mental states as the fifth domain alongside physical welfare needs

Welfare Considerations

Promoting positive welfare in pigs is not idealism — it is science. We can now measure optimism in pigs through cognitive bias tests, observe play as a validated welfare indicator and assess emotional quality through observational tools reliable enough for on-farm use. This means that higher-welfare farming is not just about reducing obvious suffering; it is about creating environments where pigs experience curiosity, play, positive social interactions and the satisfaction of foraging and exploring. These states are measurable, achievable within commercial systems and correlate with better health outcomes. Positive welfare is both morally important and practically tractable.

What You Can Do

Support farm welfare certification that includes positive welfare indicators alongside absence of suffering measures
Encourage farmers and animal carers to engage in positive human-animal interaction with pigs daily
Advocate for play-enabling enrichments to be mandatory in higher-welfare pig housing standards
Learn about the Five Domains welfare model and share it to expand the public understanding of animal welfare beyond suffering prevention
Choose pork from farms with documented enrichment programmes and positive welfare assessment scores