Pigs are playful animals whose play behaviour is an indicator of positive welfare states. Systems that enable play represent a higher standard of pig welfare.
The presence of play in pigs is a scientifically validated indicator that the animal is experiencing positive affect - a good welfare state beyond mere absence of suffering. This makes play frequency a powerful welfare assessment tool. Systems that provide space, novelty, and appropriate social groups enable play and therefore support positive welfare. Intensive systems with high density, barren environments, and constant group mixing suppress play and indicate poor welfare. Welfare certification that measures play as a positive indicator represents an advance beyond the Five Freedoms framework.