It'd be cool to randomly recieve an animal's head when butchering it.
make the odds 1/500 or 1/1000 to make them rare
craft an animal head with 2 blocks to make a mounted head
perhaps only a few animals(boar, bear, deer) or perhaps all animals. i personally would like to see squirrel heads mounted to walls.
maybe make animal heads curiosities too if you really want.