Their are 4 color variations for deer. Listed in the order or rarity they include:
Natural
Piebald
Albino
Melanistic.
Natural: The average color of any deer.
Piebald: Deer lacking some pigment of white hair
Albino: Solid white deer lacking all pigment. Nose, inside of ears, skin, hooves, etc are pink. If their is any color other than White or Pink it is a Piebald
Melanistic is an over abundant of pigmet. Making a deer darker in color. Sometimes lacking white belly and throat hair. Some deer will be jet black.