Play behavior in pigs is a reliable indicator of positive welfare states and provides a direct measure of psychological wellbeing that complements traditional disease and injury-based welfare assessment.
Play behavior in pigs provides a direct window into their psychological wellbeing that disease and injury counts alone cannot capture. A pig that plays is expressing positive affect — it has sufficient resources, feels safe, and is experiencing something approximating positive hedonic states. Conversely, the absence of play in conditions where it should occur signals welfare deficit that may not yet have manifested as disease or injury. The practical welfare value of observing play is that it provides early warning of deteriorating conditions before serious harms develop. Including play observation in routine welfare monitoring is an achievable, low-cost improvement to farm welfare assessment.