Actually...
I have yet to meet a "smart" chicken. Obviously, they're going to be less intelligent than dogs or other such animals, but they seem outrageously stupid despite their biological complexity otherwise. Maybe ours are just uniquely idiotic, but it took them WEEKS to figure out that bread was not going to try to kill them. We had to train them to go into their coop at night - they could not figure out how the ramp worked. They apparently don't grasp repeated patterns - one of them HATES being picked up, yet it still walks over to me whenever I open the door to peck at an exposed zip tie.
Is this just a Rhode Island Red thing? Our new white Leghorns aren't quite as stupid and they're a lot friendlier, though they still haven't figured out that bread is for eating, even when we break it into chunks. They still freak out at anything made of plastic, too.