Pig welfare science is advancing rapidly, informing policy, industry practice, and public understanding. Key research frontiers include positive welfare indicators, precision monitoring, and the welfare implications of genetic and production system choices.
Pig welfare research has moved beyond measuring absence of negative states toward characterising and measuring positive welfare. Play behaviourāchasing, sparring, and object play in pigsāindicates positive affect and is measurable in commercial conditions. Ear posture in pigs correlates with emotional valence: forward-tilted ears indicate positive states; back-flattened ears indicate negative states. These subtle behavioural indicators provide non-invasive, real-time welfare assessment tools applicable in commercial production environments.
Cognitive bias paradigms assess the emotional state of pigs through their responses to ambiguous stimuliāpigs in negative affective states respond more pessimistically to ambiguous cues. Research has validated cognitive bias tests for pigs housed in different conditions, revealing that housing enrichment creates more optimistic cognitive bias (positive affective state) compared to barren housing. These tests provide objective, welfare-relevant outcome measures for comparing production systems and interventions.
Automated monitoring systems for pig welfare include: camera-based activity and behaviour monitoring (detecting tail biting, lameness, lethargy, abnormal social behaviour); accelerometers tracking individual movement and activity; automated feeding behaviour monitoring detecting reduced feed intake as early disease indicator; and thermal imaging detecting fever. These systems enable earlier intervention, larger-scale monitoring than manual observation allows, and objective data supporting welfare management decisions.
Research into the genetic basis of pig behaviour and welfare-relevant traits has identified genomic regions associated with aggression, fear responses, and stress reactivity. Genomic selection incorporating behavioural traits alongside production traits creates opportunities for breeding pigs with improved welfare characteristics. Norwegian and Dutch pig breeding programmes lead internationally in incorporating welfare traits into breeding indices, demonstrating the feasibility of genetic improvement approaches to pig welfare.