To be clear, I do consider killing any animal purely to hang its horns or skin or skull on your wall is sinful. But lets look closely at your deer hunting scenario. read more
1) The typical deer "trophy" is a shoulder-mount you'd hang on the wall. This leaves the rest of the body, including all the edible cuts of meat, for you to process. The way this is done is called "caping a deer out" that is, removing the head with the neck and shoulder skin attached like a cape. read more