Play behaviour in pigs is a reliable indicator of positive welfare states and has been used to develop novel welfare assessment approaches for commercial systems.
The presence of regular play behaviour indicates that pigs are in a positive emotional state, not merely free from suffering. The absence of play is not proof of suffering, but its presence is positive evidence of good welfare. Enrichment, space, stable social groups, and good nutrition create the conditions for play. Observing play provides stockmen with a practical welfare indicator that is visible during normal daily inspection.