A black Turken hen, a Naked Neck breed, would not necessarily produce a Naked Neck Ayam Cemani if it were bred with an Ayam Cemani rooster to produce a Fibro Naked Neck (NN). Although the Naked Neck characteristic is a recessive gene, you would need to breed the F1 generation to another bird that carries the gene in order to produce chicks with the desired phenotype. The progeny would be a mix of both breeds.When non-black feathers appear in an otherwise black bird, it's referred to as leakage (typically a weak or dull color coming through). This is what your Ayam Cemani rooster is experiencing. Your Cemani rooster's progeny may have lighter or less pronounced black coloration as a result of leaking. Some progeny may not be as strikingly black as pure Cemani birds as a result, which might affect the overall look. It won't, however, necessarily alter the Naked Neck characteristic itself.