Play behaviour in pigs is a reliable indicator of positive affective states. Understanding and promoting play in farmed pigs offers a practical measure of good welfare beyond the absence of suffering.
Play behaviour offers something rare in animal welfare science: a positive, observable, measurable signal of good emotional states in farmed animals. Unlike negative welfare measures (lameness scores, lesion counts, mortality rates), play frequency directly captures the presence of wellbeing rather than the absence of suffering. Pigs in barren, crowded environments with restricted enrichment show dramatically reduced play — not because they are physically prevented, but because their motivational state precludes it. The suppression of play by hunger, pain, and environmental poverty is itself a welfare signal. Conversely, pigs given adequate space, rooting substrate, and stable social groups frequently engage in spontaneous play bouts that indicate positive affect. Incorporating play assessment into farm audits alongside conventional welfare measures provides a more complete picture of animal experience.