Summary
This literature review examines the cognitive, emotional, personality, and social characteristics of domestic chickens. In brief, the author concludes that chickens demonstrate some level of object permanence (i.e., the ability to recognize that an out of sight object still exists) and have basic arithmetic abilities. Chickens use a variety of communication methods, such signals (e.g., calls) to pass along information. They also have the capacity for reasoning, such as establishing a relationship between items that have not been explicitly compared before. In terms of social cognition, chickens can recognize individuals from their own social group, take the perspective of other chickens, and use the perspectives of others for their own benefit (e.g., only displaying certain behaviors when the dominant chicken appears distracted). Emotionally, chickens display physiological markers and behavior indicative of complex negative emotions (e.g., fear), positive emotions (e.g. relaxed) and empathy. Finally, chickens display unique personalities.
Domestic chickens are members of an order, Aves, which has been the focus of a revolution in our understanding of neuroanatomical, cognitive, and social complexity. At least some birds are now known to be on par with many mammals in terms of their level of intelligence, emotional sophistication, and social interaction. Yet, views of chickens have largely remained unrevised by this new evidence. In this paper, I examine the peer-reviewed scientific data on the leading edge of cognition, emotions, personality, and sociality in chickens, exploring such areas as self-awareness, cognitive bias, social learning and self-control, and comparing their abilities in these areas with other birds and other vertebrates, particularly mammals. My overall conclusion is that chickens are just as cognitively, emotionally and socially complex as most other birds and mammals in many areas, and that there is a need for further noninvasive comparative behavioral research with chickens as well as a re-framing of current views about their intelligence.