Validated pain assessment tools for farm animals are enabling better recognition and treatment of pain in species that evolved to conceal weakness as prey animals.
Farm animals that cannot communicate pain verbally evolved to suppress pain signs that would make them targets for predation. This evolutionary adaptation creates a welfare crisis in farming contexts where caretakers rely on visible signs to detect suffering. Animals in significant pain may appear normal to observers without pain assessment training. Validated grimace scales and behavioral assessment tools have transformed veterinary and farming practice by making pain visible where it was previously hidden. The development and adoption of these tools represents a significant welfare advance.