What do you call a young, immature female chicken that has not yet begun laying eggs and is under one year old?

A young, immature female chicken that has not yet begun laying eggs and is under one year old is referred to as a pullet. This term specifically describes female chickens during their early stages of life, typically from hatching until they reach sexual maturity around six months to one year of age.

In contrast, a hen is a mature female chicken that is typically over one year old and has started laying eggs. A broiler is a type of chicken raised for meat production, and a rooster is an adult male chicken. Thus, when identifying the stage of life of a female chicken that is young and non-egg-laying, "pullet" is the precise term to use.