-Adapted from Daily Mail
It is easy to dismiss them as bird brains but chickens may be cleverer than toddlers.
Studies show hens to be masters of a number of complex skills, including numeracy, self-control, and it is claimed, basic structural engineering.
Typically, it takes children until the age of four to accomplish some of these feats.
Christine Nicol, the Bristol University professor of animal welfare who reviewed 20 years of research on the topic, said it is wrong to think of chickens as being stupid.
Instead, we should realise that the birds have ‘many hidden depths’.
Chicken’s exhibit intelligent behaviour within just a few hours of hatching.
Newly born chicks are able to keep track of numbers up to five.
When given a choice between two groups of plastic eggs would almost invariable choose the bigger one, even when the decision was between two eggs or three.
They even pick out the larger number after the researchers tried to trick them by moving eggs from one group to another.
And their mathematical ability does not end there.
In her review paper The Intelligent Hen, Professor Nicol said the birds also seem to be born with an understanding of physics – and particularly structural engineering.
This is demonstrated by experiments in which they showed more interest in a diagram of an object that could actually be built than one that defied the laws of physics.
Experiments also show that very young chicks understand that an object that moves out of sight still exists.
In contrast, it takes babies until around a year old to grasp the key concept that out of sight does not mean out of mind.
Chickens also show basic empathy and can plan ahead and exhibit self-control until the time is right.
For instance, birds quickly learnt that if they waited longer to start eating food, they would be allowed access to it for longer.
In one study, 93 per cent of the hens tested showed self-control in this way.
Other studies have shown that children typically can’t do this kind of mental manipulation until the age of four.
Further evidence of hens’ intelligence comes from tests showing that at just two weeks’ old, they can navigate using the sun, something that requires the creatures to take account of the height and position of the sun during the day.
The final example of their intelligence is research showing that, in common with commuters on the London Underground, chickens do not invest effort in making friends with strangers.
The professor, whose review was commissioned by free range egg firm the happy egg co, said: ‘Chickens may not be about to make a significant mathematical, scientific or literary contribution to the world, but chickens have the capacity to master skills and develop abilities that a human child can take months and years to accomplish.
‘It takes a chick just a few hours to develop its representational and numerical abilities in comparison to the months and years it takes a human child to do anything comparable.
‘On the other hand, we shouldn’t go too far. No chicken has yet written a review of human intelligence.’