I know the all white is albino, and the patchy white is pibald, but I'm not sure if they have a "name" for the all black. I do know the all black whitetailed deer is the rarest. Some states have laws protecting these three rare deer. It's just a pigment problem in their skin tone. If a doe has twins, and has the black pigment gene, only one of the fawns will get it. Both the buck and doe have to have this rare gene though for it to come out.