Scientific evidence for sentience and emotional lives in farm animals is extensive and well-established. Understanding this evidence is essential to informed welfare evaluation.
The sentience of farm animals is not a philosophical conjecture but a well-evidenced scientific finding. Research has demonstrated that cattle, pigs, sheep, and even chickens demonstrate cognitive sophistication, emotional responses, and social complexity that indicate rich inner lives capable of both positive and negative experiences. Cognitive bias tests in farm animals reveal optimistic and pessimistic states reflecting underlying emotional health. Farm animals show behavioral indicators of grief following loss of companions, form preferences about their handlers, and respond to environmental enrichment with behavioral indicators of positive affect. This evidence fundamentally challenges the treatment of farm animals as interchangeable production units.