I don't know what to tell you really, my family used to breed Miniature Pinschers, and we had a runt do that to us. It was actually really weird, he died like three days after being born, mom wouldnt feed him, so we were bottle feeding, and it just happend that he had a cleft pallet. So sometimes the puppies, especially the runts are born and they are either not fully developed or they have a defect that makes it either impossible or very hard for them to digest their food.
