Assuming they are choc and not dun based, you need to ask the breeder about the parent birds. The black ones are either males with one copy of choc or females with no copies, and the choc ones are females or males with two copies. Depending on the parents' colour, you might be able to narrow it down as the gene is sex-linked. But if the father was split and the mother was choc, you won't be able to tell. If the father was split and the mother was black, the chocs are all girls, but you won't know if the blacks are split or not. And you could have some black girls.
So, you need to ask the breeder about the parents.
