Does will sometimes take on the fawns of other does, particularly those closely related to them. It is very common in deer farms, not so much in the wild. Most does in an area are related in some way, half sisters, aunt, niece, grandmother, granddaughter, etc... It's the bucks that are usually completely unrelated and often were born miles away from where they currently live. Most does give birth to a single fawn the first time they give birth(40% when they are 1 YO, 60% when 2 YO). There after, if the habitat is good, they will generally have twins. If habitat is excellent they may give birth to triplets. Quadruplets are EXTREMELY rare... I have only seen what I was near certain to be quadruplets once. As an interesting side note, when a does has multiple fawns they are often from different fathers...