With the Year of the Rooster just a cluck away, the latest research into the world's most common domestic animal shows that it's not as dumb as people may think. Here are the findings of Lori Marino, senior scientist for The Someone Project - a joint venture of animal advocacy groups Farm Sanctuary and the Kimmela Centre in the United States - who reviewed the latest research about the psychology, behaviour and emotions of chickens. The work was published in the respected Springer journal Animal Cognition.
- 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" - 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 can 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.
- They have self-control when it comes to holding out for a better food reward and they can assess their position in the pecking order, which indicate self-awareness.
- Chicken communication is quite complex, and consists of a large repertoire of different visual displays and at least 24 distinct vocalisations. This involves signals such as calls, displays and whistles to convey information. The birds may use this to sound the alarm when there is danger, for instance. This ability requires some level of self-awareness and being able to take the perspective of another animal.
- Chickens perceive time intervals and can anticipate future events. Like many other animals, they demonstrate their cognitive complexity when placed in social situations where they need to solve problems.
- They can experience a range of complex negative and positive emotions, including fear, anticipation and anxiety. They make decisions based on what is best for them, and also possess a simple form of empathy.
- Individual chickens have distinct personalities, and mother hens show a range of individual maternal personality traits which appear to affect the behaviour of their chicks. The birds can deceive one another, and they watch and learn from each other.
- Domestic chickens descended from the red jungle fowl. They are considered a sub-species of their wild counterpart, which inhabit field edges, groves and scrubland in India and South-east Asia, including Singapore. The domestication of the red jungle fowl was well established 8,000 years ago, but molecular studies suggest it could have begun as early as 58,000 years ago. Domestic chickens remain similar to their wild ancestors.