Chickens if raised in an enriched environment are extremely intelligent. They have a language, with 24 to 30 different vocalizations that they can use in combinations for varied meanings. Thus they can tell each other not only that a predator is about, but they call out if it's a hawk in the air or cat the ground, and which direction it is so everyone knows to go the other way.
They begin communication even in the egg when unhatched chicks peep to let their mom know to roll the egg for them. Chicks having been listening from within their shells to adult chickens talkin' to one another means they hatch already knowing some of the meanings of vocalizations, and obey their mother's commands. Hens teach chicks foraging skills and they are quick, sharp observers learning what's edible and what's not. They have a complex social order which gave rise to the whole human idea of a pecking order, and are primed for social interaction with other social species, like us. The pecking order is not "instinct" but a learned behavior. Hens quickly learn if chicken A beats chicken B, then chicken C will assume she would be beaten too, and will avoid the fight. The pecking order is learned by observation and deduction.
Chickens also comprehend aspects of physics, showing more interest in diagrams that adhere to the laws of physics that those which defy the laws of physics.
People who raise chickens and observe them closely can also learn the chicken language. A rolling-B sound close to bak-bak-bak is used by hens to mean "follow me" and chickens line up obeying the boss hen, and if a human duplicates that sound, they follow the human. When teaching one's chickens specific activities, it rarely takes longer than two days, and they know it well thereafter.
Simple stunts taught to a young chicken in maximum learning stage, the chicken will master in five minutes and know it for life. Silsoe Research Institute tested hens with various colored buttons and they swiftly learned that by matching colors they'd win a snack. They were then rewarded with more food if they were "patient," chickens that pecked repeatedly in frustration when food didn't appear didn't win much, but those who waited patiently got a lot. Soon they all knew to do it with patience. In their natural environment patience is not rewarding, and they go for food quickly before others in a flock get it; yet they are capable of learning to modify their own behavior, showing that they have a comprehension of "future" rewards, an ability not all animals possess.
They've been taught to use skate boards, hop through hoops, find hidden objects, fetch objects as named, usually for food rewards but many extremely tame and affectionate chickens do tricks on command in order to be praised and patted. They easily learn "no" means you're not happy with their choice, and "yes" means you're pleased, and they will strive to please a person they love. These studies were done in the Studies at Chicken Heaven On Earth Project, and the conclusion was that chickens are as smart as small children. Baby chicks understand that when an object moves out of its sight, it still exists, unlike human babies who don't figure that out until after their 12th month of life. Chicks by age two weeks have already learned to navigate through their world by taking account of the height and position of the sun.
"Hens are capable of mathematical reasoning and logic, including numeracy, self-control and even basic structural engineering," at a level equal to toddlers, according to a Christine Nicol, professor of animal welfare at Bristol University, head researcher in the study "The Intelligent Hen." Professor Nicol says, "Studies over the past 20 years have revealed their finely honed sensory capacities, their ability to think, draw inferences, apply logic and plan ahead." In her study it was shown that a typical hen is "capable of distinguishing numbers up to five and is familiar with transitive inference - the idea in logic that, if A is greater than B, and B is greater than C, then A is greater than C."
Chickens remember people who were kind to them even after months apart. They also remember other hens they used to live with and become enthusiastic over reunions. In a naturalistic setting they have orderly duties among the group checking boundaries, watching for predators, watching for reward features of the environment. In one controlled study hens and roosters were easily taught to go to bed on command, potty trained either by going to a door to be let out or pooping only on paper. Roosters were trained to crow only at 9:00 in the morning and were very reliable about it.
All chickens that interact with humans learn vocal inflections; they don't have the parrot's ability to imitate whole words and phrases, but they really do try. They easily learn the meaning and to use correctly human tonal sounds conveying laughter, anger, sadness, and questioning tone. In the controlled study all the chickens were successfully taught to say "Something Good" in a specific context: they would come to a door and ask in a demanding manner for something good, and receive snacks. If not given the snack they'd repeat "something good" in a more questioning tone of voice.
Chickens in cages or the hellish so-called "cage free" environment crowded on barn floors knee deep in chickenshit are relatively stunted intellectually. Even chickens with free run of a small but largely sterile outdoor area, fed by having grain thrown at them and otherwise ignored, languish in their unenriched lives and seem pretty dumb. But with complex interactions with people and a naturalistic environment not restricted to ground and box, with plenty to hunt or do, their cognitive abilities flourish and deepen.
Siobhan Abeyesinghe published a seminal study "Do Hens Have Friends?" noted in an interview that humans "have this psychological shielding to devalue animals we use for meat, so we feel less concern about them." But fact is, when you eat that piece of fried chicken, you've eaten a sentient being smarter than your two year old kid.
Chickens learn tricks in mere minutes.

The chickens' enriched environment.

The Agonizing Love of a Hen

Skateboarding chicken.

Surf chickens!


