You might not want to read this if you're about to attack a chicken salad sandwich, but researchers say they have found that chickens are not as bird-brained as we think.
In fact, says Lori Marino of The Someone Project, chickens have distinct personalities, know their place in the pecking order, and can reason by deduction, something humans don't generally learn until age seven.
Marino reviewed the latest research about the psychology, behavior, and emotions of the world's most abundant domestic animal. Her review is published in Springer's journal Animal Cognition.
"They are perceived as lacking most of the psychological characteristics we recognize in other intelligent animals and are typically thought of as possessing a low level of intelligence compared with other animals," Marino says. "The very idea of chicken psychology is strange to most people."
Yet, she said, research has shown that chickens have some sense of numbers. Experiments with newly hatched domestic chicks showed they can discriminate between quantities. They also have an idea about ordinality, which refers to the ability to place quantities in a series. Five-day-old domestic chicks presented with two sets of objects of different quantities disappearing behind two screens were able to successfully track which one hid the larger number by apparently performing simple arithmetic in the form of addition and subtraction.
Chickens are also able to remember the trajectory of a hidden ball for up to 180 seconds if they see the ball moving and up to one minute if the displacement of the ball is invisible to them. Their performance is similar to that of most primates under similar conditions.
Unlike many humans, chickens can exercise self-control when it comes to holding out for a better food reward, Marino said. They are able to self-assess their position in the pecking order -- indicating some degree of self-awareness.
Chicken communication is also quite complex, and consists of a large repertoire of different visual displays and at least 24 distinct vocalizations, she said. Chickens perceive time intervals and can anticipate future events. Like many other animals, they demonstrate their cognitive complexity when placed in social situations requiring them to solve problems.
The birds are able to experience a range of complex negative and positive emotions, including fear, anticipation, and anxiety. The birds can deceive one another, and they watch and learn from each other.
"A shift in how we ask questions about chicken psychology and behavior will, undoubtedly, lead to even more accurate and richer data and a more authentic understanding of who they really are," says Marino.