The space allowance provided to pigs significantly determines their welfare through effects on movement, social behaviour, air quality, and aggression.
Pig space allowance welfare is a direct relationship: more space enables more natural behaviour, reduces competition for resources, allows better air quality, and reduces injury from aggression. The minimum legal space allowances in the EU and UK have been set partly on productivity and economic grounds rather than purely on welfare science, and are lower than welfare scientists recommend for adequate expression of natural behaviour. Higher-welfare certification schemes that require greater space allowances demonstrate that production is commercially viable at these levels, challenging the narrative that welfare improvements at the minimum standard cannot be exceeded without economic unsustainability.