I have a few chickens that I got last summer as chicks. They are brothers and sisters and they are totally different sizes. How old does a chicken have to be before it will be full grown? Is a bantam the smallest size of chicken because I have a hen that is smaller than my bantams.
Pullets and cockerals are considered hens and roosters at 1 year old, so that seems to be the number most people refer to, but different breeds mature at different rates, what breeds are your chickens?