Play behavior in pigs is a reliable positive welfare indicator, with research demonstrating that pigs in enriched environments with stable social groups allocate significant time to play that disappears under stress and poor welfare conditions.
Play behavior research in pigs has transformed understanding of positive welfare indicators in farm systems. Rather than focusing solely on absence of suffering, play measurement provides insight into the presence of positive states - animals with time, energy, and security available for play are meeting their basic needs with resources to spare. Farms and experimental conditions that produce high play rates are achieving good welfare by this metric; those where play is absent despite similar ages and health states are revealing welfare deficits through behavioral analysis. The practical application: welfare auditors and researchers can use play bout frequency and duration as a rapid, non-invasive positive welfare indicator during farm visits.