Research into positive emotions and play behavior in pigs demonstrates that welfare assessment must include positive states, not only absence of negative experiences.
The scientific documentation of positive emotions in pigs has transformed the welfare framework for pig farming. Welfare is no longer defined only as the absence of pain, fear, and disease but requires the presence of positive experiences including play, curiosity, and social comfort. This shift has profound implications: a pig housed in conditions preventing injury but also preventing all play, exploration, and social positive interaction is not experiencing good welfare despite meeting traditional minimum standards. Welfare-certified production systems increasingly require evidence of positive behavioral indicators, not just absence of negative ones — a higher and more genuinely welfare-protective standard.