Play behavior in pigs is a reliable positive welfare indicator that enrichment programs can encourage.
Play behavior in pigs signals more than just the absence of suffering — it indicates that animals are in a positive affective state with sufficient resources to invest energy in non-essential behavior. Pigs in barren, crowded, or socially stressed conditions stop playing — the behavior is exquisitely sensitive to welfare conditions. Enrichment programs that increase play frequency are therefore not merely providing entertainment but addressing fundamental welfare quality. The inclusion of positive welfare indicators like play in assessment frameworks represents a maturation of welfare science beyond simply measuring suffering toward measuring flourishing.