In nature, when one or more members of a litter are unhealthy or stillborn, they put the rest of the litter at risk. A dam’s instinct will tell her that she must remove the unhealthy and stillborn puppies from the den. Most of the time, domestic dogs will simply reject unhealthy puppies, pushing them away from the nest. They may carry stillborn puppies away from the nest or “bury” them someplace in the house. However, if instinct takes over and the puppies are young enough, the dam might kill and eat unhealthy puppies, as well.