Sheep have a sophisticated facial expression repertoire that scientists use to assess pain and emotional state. The Sheep Pain Facial Action Coding System (ShPACS) is transforming farm welfare assessment.
The development of validated facial action coding systems for sheep has been a breakthrough for farm animal welfare assessment. Previously, identifying pain in stoic prey animals like sheep required invasive physiological tests or relied on subtle behavioural changes that untrained observers often missed. Facial coding provides a rapid, non-invasive, repeatable tool that stockpeople can apply on farm. Training stockpeople in facial pain assessment improves their ability to identify suffering animals and treat them more promptly. The tool also supports research into analgesic effectiveness and welfare outcome monitoring in routine farm procedures.