A pair of chickens is simply called a pair of chickens. They could also be called a mated pair (if they are that), a small flock, or even a couple. Or, be creative and make up a name that is descriptive and unique to that one pair of chickens.
Slick chick.
kickin' chicken
In the film, Chicken Run, the chicken that knits is called Babs.
hen penhen pen
Thick chick.
A set ordered pair is...called a set ordered pair
a mother chicken is called a hen.
A pair of pheasants is called a brace.
A chicken.
I believe it's hen pen
A baby chicken is called a chick.
A chicken can be either male or female. The male chicken is called a rooster, while the female chicken is called a hen.