depends on the genes of the parents. Black is dominant, so if you breed 2 yellows, but one of the yellows carries black, you will get both black and yellow puppies. any breed works this way. for example, Happy's sire is red merle, because of that I know that Happy carries the red gene, even though she herself is black. however because red is recessive, if I wanted to breed her and I wanted reds, I would have to breed her to a dog that also carries red, if I bred her to a black that did not carrie red I would get either black or blue merle pups, but red would not be possable.