Lindsay, I don't have blacks but they are probably the most popular color so you should be able to find some close by. I am not sure if most people will know for certain if they have complete silver based line. Most breeding blacks prefer Gold based lines. Though some blue lines are supposedly based silver because it offers advantages for better blue color. So those breeders might use a black bird from their Blue/Blue crosses to reinforce their matings. But it still allows them to stay inside a silver based line. I am curious, what would you be using this bird to accomplish?