Answer:
A white deer is an albino deer and it's extremely rare.
They are technically called piebald deer (deer that have a lack of pigment in patches around it's body that appear white). In mythology, it's said that if you see one in the wild then you are considered blessed and very lucky in life.
Explanation:
the chances of an albino deer being born are about 1/20000. Hope this answered your question :)
