Oral stereotypies in pigs — repetitive, functionless bar-biting, rooting on concrete, and sham-chewing — are reliable indicators of poor welfare and frustrated behavioural needs.
Oral stereotypies in pigs are a welfare indicator with a clear causal story: pigs are highly motivated to root, chew, and manipulate their environment; when confined in barren environments that prevent these behaviours, the motivation accumulates and finds expression in repetitive, functionless movement. Bar-biting in sows is one of the most visible and well-documented examples of welfare compromise in commercial pig farming, directly associated with gestation crate confinement and barren environments. The welfare significance extends beyond the stereotypy itself — it reflects a chronic state of motivational frustration that affects psychological welfare across all domains. Management changes that provide rooting substrate, increase social contact, and allow more movement dramatically reduce oral stereotypy frequency in affected populations.