Sorry, I sent this down a rabbit hole unrelated to the subject. If you use the protein based stuff place it will away from prying eyes and post your results!!!
This is from WAC 246-203-121 Disposal of dead animals.
(c) "Dead animal" means the carcass or tissue from an animal
So that includes gut piles if you read it that way.
(g) "Natural decomposition" means natural decay on the surface of the ground without cover material.
(2) Disposal methods.
(a) Within seventy-two hours after death or discovery, the owner of a dead animal or, if the owner of the animal cannot be identified, the owner of the property on which the animal is found must properly dispose of the dead animal. A dead animal must be covered
or otherwise removed from public view immediately upon discovery by the person responsible for disposing of the dead animal.
(c) The person responsible for disposal of a dead animal must dispose of it by burial, landfilling, incineration, composting, rendering, or another method approved by the local health officer
(such as natural decomposition) that is not otherwise prohibited by federal, state, or local law or regulation.