Chick development included sensory systems, including sight, hearing, smell and touch, all begin to develop prior to hatching. The shell of the egg does not shield the developing embryo from sound and light, for example, and the external environment influences the neurological development of the chick. When the chick hatches, he or she already knows some characteristics of the hen’s call. Chicks are very precocial, and quickly learn essential associations that are necessary for survival, such as how to identify edible feed stuffs, recognize danger, and keep up with their mother.
At hatching, chicks instinctively follow the first moving object they see and learn its characteristics, a process known as imprinting. Under natural conditions this is normally their mother but, when reared in an artificial environment such as a laboratory, they will imprint on the first moving object they encounter.
Newly hatched chicks begin to explore and peck at small, spherical, food-like objects and their pecking improves in accuracy over the first week of life.Newly hatched chicks must learn to recognize food, so the hen’s behavior is very important in encouraging chicks to peck at edible items. The hen directs her chicks to appropriate food items by calling and pecking at the ground.
Behavioral research has revealed that hens demonstrate remarkable ability to adjust to the foraging skills of their chicks. In a study conducted at Bristol University, chicks learned to eat color coded feed. While hens were taught that one color of feed was edible and another color inedible, their chicks were taught the opposite. When the hens observed chicks making apparent errors in food selection, they increased the intensity of their feeding display, scratching and ground pecking more, in response to perceived errors by their chicks.
In an interview, John Webster, emeritus professor at Bristol University, stated, “What this tells us is that the mother hen has learnt what food is good and what is bad for her, that she cares so much for her chicks she will not let them eat the bad food and she is passing on to her young what she has learnt. To me that is pretty close to culture—and an advanced one at that. Chickens are sentient creatures and have feelings of their own.
During the first four days post-hatching the chicks remain very close to the hen, who takes them under her wings and crouches over them. This brooding behavior, which can occupy as much as 2/5 of the daily activity of a hen, can be initiated by either the hen or her chicks. The chicks, for example, may insist on being brooded by peeping loudly and pressing up against the hen. Brooding keeps the chicks warm, and a hen will brood her chicks during inclement weather, or will call them to hide under her at signs of danger. Mother hens are very protective of their young and, if their camouflage and other defenses fail to avoid detection, a hen will become raucous and draw potential predators to herself in an attempt to divert attention away from her chicks.
The chicks follow the hen on walking and foraging trips along the home range, and the hen keeps them nearby by clucking to them. If they wander away from the hen and the rest of the brood, chicks are often able to find their way back to the nesting site.
By ten days of age, chicks begin moving further away from the hen, sometimes traveling out of her sight. Frolicking—a behavior in which one individual runs toward another with wings raised or flapping—peaks at 12 days of age.86 Chicks will copy each other’s behavior when playing, a psychological phenomenon known as social facilitation.
A social order becomes apparent by 5-6 weeks of age. By 6-7 weeks, the chicks begin to fly well enough that they move to safer roosting sites above ground with the mother hen. By approximately 8-10 weeks post-hatching, the chicks start to forage independently of their mother, although they continue to associate with the brood and roost near the adult flock.91 By approximately 18 weeks, the young birds join the rest of the flock.