Chickens, usually considered a relatively foolish animal, are actually smarter than most others! It turns out that chickens can be more intelligent than dogs and cats, and second only to humans and other primates. What distinguishes chickens from other animals?
It's their ability to anticipate future events based on past occurrences and the ability demonstrate self-control. Chickens are also able to feel stress, another feeling they were not previously thought capable of having, which raises a red flag for animal rights advocates because of the implications associated with being killed for food.
(Source) OMG Facts