Play behaviour in pigs is a reliable indicator of positive welfare states, with farming systems that facilitate play producing healthier, less aggressive, and more productive animals.
Play is not merely a luxury in pigs but a welfare indicator with direct implications for farm management. Playful animals are in positive affective states; absence of play signals chronic negative states from overcrowding, environmental barrenness, or fear. Play behaviour measurement is being incorporated into welfare assessment protocols as an outcome-based positive indicator. Systems that facilitate play — adequate space, enrichment materials, stable social groups — simultaneously reduce aggression, tail biting, and other redirected behaviours. The economic case for play-enabling systems is therefore aligned with the welfare case.