There is increasing awareness of, and concerns with the effect chronic pain may have on farmed animals. Chronic pain is probably the product of evolutionary processes that make the individual less vulnerable to attack and so enhance survival. However, it may simultaneously compromise both welfare and production (Crook RJ, Dickson K, Hanlon RT, Walters ET. Curr Biol 24:1121–1125. https://doi.org/10.1016/j.cub.2014.03.043 , 2014). Chronic pain is not simply a temporal continuum of acute pain but the perceived result of a series of peripheral, spinal and central mechanisms. Physiological changes at multiple levels within the nociceptive pathway may facilitate or mitigate the development and perception of chronic pain. Understanding how chronic pain develops is the first step in creating strategies to mitigate it in farmed animals.