Chickens Have Personalities and May Have Impulse Control Comparable with Monkeys

Like humans, chickens display different personalities and some can display impulse control that is comparable to monkeys.

New research suggests that birds that tend to stick close to the coup are more perceptive and are better able to control their impulses than their more exploratory friends.

According to the authors of a study published in Biology Letters, this could be the first time scientists have examined the link between a chicken's propensity to explore and their ability to control their movements.

In this particular study, scientists examined links between inhibition and ranging behavior in 19 free-range chickens, all broiler males. The chickens were categorized as high rangers or low rangers, depending on how far they ventured from the poultry house. High rangers, for example, typically traveled further.

Researchers used the cylinder test to gauge the inhibition of the individual chickens and noted down any differences between the two groups. To succeed at the task, the animal were required to inhibit their initial impulse to reach the food at the center of a transparent cylinder and collect the food from one of the side openings.

First, the chickens were trained with an opaque cylinder. Then, they were tested 10 times with a transparent cylinder.

According to the results, high rangers were the worst performers, showing low levels of inhibition and obtaining lower scores on the test than any species tested. However, low rangers achieved higher scores, equivalent in some cases to those of some monkeys and prosimians.

The key difference between the two groups, say researchers, was that low rangers managed to improve their performance over time. In other words, they did better in the last five attempts than they did in the first five. The high rangers, however, did not.

The study's authors suspect this disparity comes down to personality traits. Low rangers tend to be more fearful, vigilant and passive, and display a greater corticosterone response when exposed to stress, they say. In essence, they are more reactive than their high ranging counterparts. It, therefore, makes sense that they are also more attentive to their surroundings and may be more flexible in their behavior.

The result was not all that surprising. Previous research has shown that less exploratory chickens had better spatial memory than more exploratory chickens. Here, spatial memory refers to an awareness of—or attentiveness to—one's surroundings. The same research also found that individual birds display differences in ranging behaviour that remain stable over time, indicating differences in personality.

The researchers, therefore, expected high levels of ranging to be associated with lower levels of inhibition.

It adds to a growing body of research showing animal personalities are far more complex than once thought. In previous studies, scientists have shown cows can be optimistic or pessimistic, orcas display human-like traits like affection and extraversion and even guppies appear to display different coping styles when exposed to stress.

Chickens
Male broiler chickens display personalities too. New research suggests birds that don't stray too far from the coup are more perceptive than others. NatalyaMatveeva/iStock