dam killed puppies

Question
Hello, yesterday my 2,5y Yorkie whelped 5 puppies, her first
litter. She was a great mother, but today she killed them
and ate some. She is very loving dog, thats why I dont
understand why she did it. We've got also 10 months Yorkie
female, she was allowed to be near the puppies by new
mother, while we were in room with them. But today when I
opened the door both dogs were inside and puppies were dead.
I think its my fault because I havent been careful and let
the other dog come into room and thats why she killed them.
We all are really sad and dont know why this happend. She is
acting like puppies are still upstairs. And I dont know how
to behave to my dog now. Thank you very much for your
answer... Martina

Answer
Take that bitch to the veterinarian immediately.  She may need some hormonal assistance and she should be evaluated for nutritional deficiency as well as any possible physical problem.  As soon as she has recovered physically (ask the veterinarian) have her SPAYED.

It's more likely the second bitch killed the puppies but I can't see anything from here.  A bitch with newly whelped puppies MUST BE KEPT STRICTLY ISOLATED FROM OTHER DOGS.  There are tens of thousands of dogs dying in kill shelters, on streets and at the hands of miscreant humans every day.  The world doesn't need any more.  Maintain your dogs as companions only.  Being a breeder requires knowledge of dog behavior and genetic evaluation of breeding stock.  This event means nothing regarding the temperament of your dogs toward humans but it certainly indicates the dogs you have should not be bred.