Polish chickens are like fluffy bobble-head dolls. Their heads dart around like those of regular chickens and their poof of head-feathers bobs in the opposite direction. One of mine has such thick feathers on her head that I'd have to lie prostrate on the ground and look up in order to see her eyes peering out from underneath.
For about a hundred years scientists argued about the relative intelligence of Polish chickens compared to others. Charles Darwin wrote about a crested hen that couldn't find her way back to her feeding station after he moved her a hundred yards away. Then in 1959 a scientist by the name of Requate trimmed the feathers of their crests and found that they reacted to stimuli (science talk for things like offering worms or making noises) in the same way as other chickens. I don't know if his results were confirmed. If his experiment can't be replicated, it's not valid science. He may have just been dealing with exceptional crested chickens.
So the mind of the Crested Polish chicken may still be a matter for debate. What's certain is that the shape of their heads is different. Their brains and skulls been studied extensively by two scientists at the University of Dusseldorf, Germany. Frahm and Rehkamper pose the age-old chicken-and-egg question:
"Does the feather crest eventually alter the shape of the skull and thus the brain, or are the alterations in brain shape the cause of the protuberance and the feather crest?"
Yet another profound evolutionary question to which we may never have an answer.