I'm gonna say injury too. I just don't think a fawn with that type of birth defect could have made it in the wild. It would have been coyote food.

It could do alot better if it was injured later in life and was in fairly good shape at the time.

The muscles in the front end do seem to be over developed or maybe it's just the angle of the last pic. These animals never cease to amaze me as to their tuffness.