Advanced research on positive emotional states in pigs demonstrates that specific enrichment types produce measurable improvements in affective state beyond mere behavioral engagement.
Advanced positive emotion science in pigs has moved beyond establishing that enrichment is beneficial to identifying which enrichment types produce the strongest and most durable positive welfare states. Rooting material quality has emerged as the most important variable — pigs with deep, manipulable rooting substrate show positive welfare indicators that persist throughout the production period, not just immediately after enrichment introduction. This specificity matters for welfare standards development: generic enrichment requirements are less effective than substrate-specific mandates that guarantee rooting behavior expression.