I purchased my AKC registered western German Shepherd from a reputable kennel in Romania where I had previously purchased her distant cousin. This was her first litter and she’s 2 1/2 years old. She has a tendency to get anxious when I’m not with her but not destructive. She had given birth to 7 puppies already. I stepped out of the birthing room for a few moments and when I went back in she was eating the 8th puppy she had just given birth to. Why did she do this and do I have to worry about the rest of the puppies. Her cousin never did this before. She is being a great mother, nursing and cleaning the newborns. The only things she ever destroys in the house are her stuffed animals. I don’t know what to do. I really don’t want to get rid of her. She is perfect in every other way. I’m worried she might harm another puppy if I leave the room or go out somewhere. How old do the puppies have to be till they are out of the danger zone of being eaten if she will do this again? Did she eat the last one because she was anxious or it was sick? The puppy was alive when she had started to eat it. Never in my 20+ years has this happened to me before with my dogs.
There are many factors leading to mothers killing/eating their offspring in mammals. The ones that seem applicable to yours are:
First-time mother: First-time mothers are always anxious, whether they are cats, dogs, hamsters or humans. They suffer post-birth syndrome more than experienced mothers. I have seen cat and hamster mothers leaving their litter unattended and grooming themselves, irrelevant to the cries of the newborns. There is little to do in this case, other than hope that she will get back to her senses.
Large litter: While, 8 puppies are not too large for a german shepherd, it is still on the high side. She might have thought there is no way she can raise all eight of them and decided to cull the litter to a raisable size.
Sick baby: Giving birth is exhaustive for the mothers. If one of the babies is sick, she might have thought to absorb some of the nutrients back from a baby which wouldn't survive anyway.
Mother deficient in some vitamin/mineral: As Elmy suggested, she might have some deficiency. There is a hypothesis called cravings based on needs. This is mostly a hypothesis, but it explains a lot of otherwise hard-to-explain behaviour. If the mother is deficient in something, she might have thought she can make up for the deficiency by eating the puppy.
It has been longer than two days now since the question is asked and I do not expect her to eat any more of her babies at this point. She is probably overcoming her PBS and raising her puppies as a good mother. As long as she feels safe, there should not be any further cannibalism. Since she trusts you, you spending more time with her might help your dog.
I hope this helps.