In Cattle it is called a wry face, however I have never seen it in a deer. Goats sometimes have wry tails which is a DQ in the show world. This rare condition is believed to have something to do with the calcium levels in the mother, but that is just a belief and I can't offer any research on the subject. It is included in the catagory of defects called parrot mouth, underbites, monkey mouth, wry face, etc.