WHY did the chicken cross the road? With the help of a new “UBD guide” to the brain of the farmyard favourite, scientists may one day be able to tell us.

And the answer might prove more interesting than you suspect – for the bird that has been the butt of jokes since jokes began is actually very bright, indeed.

“In almost every language there is a joke about birds, particularly chickens, being dumb,” says Charles Watson, professor of health sciences at Curtin University.

“But birds, in general, have smarter brains than most mammals. They run rings around dogs and probably dolphins, too. Most birds have incredibly good memories, learning and problem-solving abilities.

“In fact, birds’ brains have to be even more efficient than mammals’ because their brains have to be small and light in order for them to fly. Land mammals have the luxury of having any sized brain as long as they have the neck muscles to support it, but birds have a power-to-weight issue so they have very clever brains in a very small space.”

In 1982, Professor Watson, with collaborator Professor George Paxinos, mapped the rat brain in stereotaxic, or three-dimensional, detail. The Rat Brain Atlas, with its UBD-style coordinates, revolutionised neuroscientists’ ability to study the brain in fine detail and it remains the only Australian book in the top 50 scientific publications of all time.

The scientists have since published “maps” of the mouse and human brains.

Now, with the help of Spanish genetic mapper Luis Puelles, they have done the same for the chicken brain.

“What people haven’t realised is that although we think of birds as being so incredibly different from other vertebrates, when you look at their brains they are actually very similar,” Professor Watson says. “Apart from the bird’s forebrain, which has had to evolve differently, they have the same things, from top to bottom.

The Chicken Brain Atlas (Elsevier/Academic Press) took seven years to produce and for the first time includes genetic information and a map of each segment of the brain stem.

“For the past 100 years most of the scientific studies of developing brains have been in chickens because it’s very easy to access them. You can just put in a probe and see the embryo developing on top of the yolk sack. In mammals it is very difficult to see them developing in the uterus,” he says.

“A lot of the questions that scientists want to ask about the brain can be most easily answered by looking at the chicken brain, rather than mice, cats or donkeys.”

The fact that chickens in captivity aren’t as smart as they could be is not their fault, but ours.

“Chickens have brains as good as any other bird, but we just don’t allow them to develop it. They lead incredibly deprived lives. If you stuck humans in a stainless steel cage all their lives and didn’t allow them to do anything or go anywhere, they wouldn’t look too bright either.”