I don’t see why this isn’t a skill on its own already but is part of the survival skill. This doesn’t make much sense since survival also encompasses thing such as looking around in bushes, knowing how to make pine needle tea and how to make stone tools. But none of these things are going to make you better at cutting up corpses. Nor will cutting up corpses magically make you better at any of these.
I would imagine this skill improving not just the amount that you harvest form a corpse but that it also decreases the amount of time you spent butchering, with lower levels mostly increasing the returns you get and the higher levels mainly decreasing the amount of time you spent butchering a corpse. It would also be need to lock certain types of butchery behind a certain amount of butchery skill since your not gone know how to quarter/skin a corpse effectively or how to field dress it without adequate experience. This skill would obviously be trained by first just hacking apart corpses and later by preforming actual butcheries on (larger?) corpses.