When we first started breeding Ameraucanas, seventeen years ago, a large majority of the black and blue cockerels would have extra gold or silver in their hackles and/or saddles by the time they were butcher size (about 5 months). They are very good to eat! Only a few cockerels would be free of any extra color (leakage). The breeders would be selected from the ones that didn't have any leakage. Several years of repeatedly breeding for clean hackles and the opposite appeared! The large majority of males were clean and only a few had leakage but it would still occur in some. We went 5 years without adding any new breeders, then purchased five cockerels. Unfortunately the leakage problem has increased with their addition. I've been told both "using a black cockerel out of a pair of blues doesn't matter, because if you can't see the blue-it isn't there," and by someone else "don't use a black cockerel out of a pair of blues because he will mask (hide) leakage modifiers. The past five years breeding experience-I'm heavily leaning to the theory of not using a black cockerel out of a pair of blues. it may take another 17 years to definitely confirm that concept.
Don't throw out the baby with the bath water-keep the black cockerels with either no leakage or at least the ones with the least amount, if you don't have any that are well built without any leakage.
Best wishes, don't give up, breeding show birds isn't always easy.