United Poultry Concerns
14 July 2009
Pain and Suffering in Birds
Karen Davis, PhD, President, United Poultry Concerns

Chickens and turkeys - birds - experience pain, panic, fear and distress the same as other animals including humans. Pain receptors, thermo-receptors, and physical-impact receptors responsive to noxious (tissue damaging) stimuli have been identified in birds and characterized in chickens. Like mammals subjected to painful stimuli, chickens show a rapid increase in heart rate and blood pressure, and behavioral changes consistent with those found in mammals indicating pain perception - efforts to escape, distress cries, guarding of wounded body parts, and the passive immobility that develops in birds and other animals subjected to traumatic events that are aversive and that continue regardless of attempts by the victim to reduce or eliminate them (Gentle 1992).

Michael Gentle states in “Pain in Birds” that comparing the physiological responses of the nociceptors (pain receptors) found in chickens with those found in mammals, including humans, “it is clear that in terms of discharge patterns and receptive field size, they are very similar to those found in a variety of mammalian species.” Birds, like mammals, he explains, have “a well developed sensory system to monitor very precisely external noxious or potentially noxious stimuli.” He concludes that the “close similarity between birds and mammals in their physiological and behavioral responses to painful stimuli would argue for a comparable sensory and emotional experience” (Gentle 1992, 237-238, 243).

Birds are Intelligent Beings

In addition to comparable sensory and emotional experiences, birds have cognitive abilities “equivalent to those of mammals, even primates” (Rogers1995, 217). This conclusion is shared by the Avian Brain Nomenclature Consortium, an international group of scientists. In a paper published in Nature Neuroscience Reviews in 2005, the Consortium presented the overwhelming evidence showing that a bird’s brain is a highly complex organ of which fully 75 percent “is an intricately wired mass that processes information in much the same way as the vaunted human cerebral cortex.” In light of this evidence, the Consortium is calling upon scientists around the world to adopt a new language to describe the various parts of the bird’s brain in recognition of what is now known about avian intelligence upsetting the “old system [that] stunted scientists’ imaginations when it came to appreciating birds’ brain power” (Weiss 2005). As for chickens in particular, scientists observe that “chickens evolved an impressive level of intelligence to help improve their survival” (Viegas).

The question is what will we do with this knowledge?


  • [The] Avian Brain Nomenclature Consortium. 2005. Avian Brains and a New Understanding of Vertebrate Brain Evolution. Nature Neuroscience Reviews 6 (February): 151-167. www.Avianbrain.org.

  • Gentle, Michael J. 1992. Pain in Birds. Animal Welfare 1: 235-247. Universities Federation for Animal Welfare.

  • Rogers, Lesley J. 1995. The Development of Brain and Behaviour in the Chicken. Oxon, UK: CAB International.

  • Viegas, Jennifer. 2005. Study: Chickens Think About Future. Discovery News July 14.

  • Weiss, Rick. 2005. Bird Brains Get Some New Names, And New Respect. The Washington Post 1 February, A10. www.upc-online.org/alerts/20105post.htm.

From Karen Davis, PhD, Prisoned Chickens, Poisoned Eggs: An Inside Look at the Modern Poultry Industry . Summertown, TN: Book Publishing Company, 2009. pp. 158-159.

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