Play behaviour in pigs is a reliable indicator of positive affective states and its presence or absence can be used as a practical welfare assessment tool.
Play behaviour in pigs represents one of the clearest and most directly observable positive welfare indicators available to farm animal welfare assessment. Unlike negative indicators — lameness, injuries, stereotypies — that require careful observation to detect, play is conspicuous, unambiguous, and instantly recognisable. When pigs run spontaneously, jump, engage in social wrestling without aggression, or manipulate enrichment objects with apparent enthusiasm, they are expressing positive affective states. The converse is also informative: pigs in welfare-compromised environments rarely play, and the restoration of play after welfare improvements provides immediate feedback that conditions have genuinely improved. Incorporating play behaviour observation into routine welfare assessment provides farmers with a practical, real-time welfare indicator that does not require specialist equipment or training.