I think I have 2 extended black hens. they look like ravens, no trace of any other colour.
not all the black hens.
to know if a black hen is true extended black ,you need to hatch chicks from her with any rooster ,all her chicks should be black . cockerels and pullets . Extended black is the most dominant in all the varieties.
mate your hens to your new silver cuckoo and see what they throw out .nice to new ,maybe you havea hidden treasure .
chooks man