Deb Olin Unferth in the November Harper's:
In nature chickens live in smallish groups in overlapping territories. They have complicated cliques and can recognize more than a hundred other chicken faces, even after months of separation. They recognize human faces too. They have distinct voices and talk among themselves, even before they hatch. A hen talks to her eggs and the embryos answer, peeping and twittering through the shells. Adult chickens have at least thirty different categories of conversation, centered around, to name a few, mating, eating, nesting, rearing, and warning, each with its own web of coos and calls and clucks.
According to the animal-studies professor Annie Potts, hens all have different dispositions. They have best friends and rivals. They are surprisingly curious. They play and bathe in the dust. A flock of chickens in nature resembles a lively village, with the males crowing and dancing around the females in courtship, the young ones sparring, most of them climbing into the trees at night to sleep.
Their eyes are especially ingenious. Human eyes work together and focus on one location but chickens' eyes work separately and have multiple objects of focus. A hen can look at a morsel on the ground with one eye and scan the area for predators with the other. When you see a hen cocking her head at you at different angles, she is getting a series of snapshots from different perspectives, studying you. If you study her back, she'll step closer and sit next to you. When I sit in a barn with a flock of hens, they come right over to me, hop up on my stool, poke at my pen, look into my face.