Both Boared and coyoteseeker are right, about the mange and about bagging the carcasses respectively. It's not absolutely necessary to bag and burn them b/c once the animal is dead, they won't have anything to feed on after the blood runs cold, however, it is a better idea to go ahead and do so, b/c if they have mange, it is likely that they have other diseases as well, b/c they can't fight them off as easily as they would if they were healthy.