Botulism is very rare and needs a very narrow range of environmental conditions to grow and build up the toxin: low oxygen, salt, acid, etc. Think canned foods. Meat that has been unrefrigerated for a few hours will not develop botulism. Meat that has been rotting in the open air will almost certainly not develop botulism. If rotten meat is cooked well (high heat for a long time) it will not hurt you. Been there, done that, multiple times. You can eat old road kill if you cook it well enough.