The color can vary from chick to chick. Sometimes mine will have partially colored beaks, but by the time they're a few months old, the white part will have grown out on the beak. I've never had a black one hatch with a completely white beak, tho, so if that were to happen, I'd wonder about the quality of the stock. I've never seen MMM JG's in person, but the description of your chick sounds right.