Social play is a marker of positive welfare in pigs, and its presence or absence reflects the quality of the social and physical environment provided by the farming system.
Play in pigs is not a trivial luxury but a biologically significant behaviour that reflects genuine positive affective states. Pigs play when they feel safe, well-fed, and socially secure — conditions that also support other positive welfare outcomes including reduced stress, better immune function, and improved growth. The suppression of play in intensive systems characterised by barren environments, overcrowding, and chronic stress is therefore both a symptom and a cause of poor welfare. Monitoring play behaviour as part of welfare assessment provides a sensitive indicator of system quality that goes beyond the absence of clinical disease or injury.