The scientific study of animal welfare requires specialized methodologies for measuring subjective states in non-verbal beings, and evidence quality standards shape what interventions are adopted.
Animal welfare science faces the fundamental challenge of measuring subjective experience in beings that cannot verbally report their states. Multiple converging lines of evidence — behavior, physiology, cognitive indicators, and preference expression — provide a composite picture of welfare quality. The field has evolved from a focus on preventing suffering to also measuring and promoting positive welfare states: opportunities for play, exploration, and social bonding. Rigorous welfare science requires interdisciplinary approaches and ongoing methodological innovation.