A local farming friend wondered out loud what was happening to the carcasses he was putting in a remote pasture. He said there is never anything left of them, not even bones, and it usually doesn't take very long - no more than 2-3 days. He runs a small hog confinement and every so often there is a pig that "loses his squeal". He didn't think he had coyotes because he'd never seen one.
Not one to believe that aliens would remove rotting flesh, I visited the area with a spotting scope one evening and watched 6 coyotes munching on 3 piglet carcasses for over 1/2 an hour. Further conversations with my friend convinced him of the need to have these coyotes harvested next fall (I like the fur). He asked me if I would do the job.
So, coyotes like the other white meat just fine. If you are set on baiting, you might visit a hog confinement near you, explain why you are there, and ask for a few dead piglets or a dead hog. Be aware, they do not smell like bacon cooking, so you may want to bring something to put them in while you transport them. If you are hunting private land, also be aware that the landowner may not want you to haul dead animals onto his land (disease?).
If you leave the carcasses out overnight, they may be gone in the morning. If its coyotes, they may come back to check the spot. If its aliens . . . you're on your own, lol. Good luck! /ubbthreads/images/graemlins/laugh.gif