As someone who hunts in Idaho and has had lots of experience with using animals (horses) to pack things in or out, I can tell you that animals have a great sense of smell. This sense is also used as a defense mechanism. To get a horse or mule to pack out a dead animal usually takes a lot of training. The scent of a dead animal is pretty potent to another animal. The last thing I want to be smelling 2 or 3 weeks down the road as I'm hunting is rotting guts, either. It is a deterent. Except for the animals that feast on it!