Juvenile chickens are too old to be chicks anymore, but are not matured enough to mate and lay eggs. Most heritage chickens mature around 16-18 weeks. Some breeds, such as the Phoenix, can take as long as 22 weeks to mature. The feathers of juveniles can go through dramatic changes; as they build up the different layers of colour that will form their adult plumage.
Note: we have not started hatching chicks yet in 2016.