I think most breeders usually do it from 2-5 days of age?
Who did the tail docking? What did the vet say? How many puppies were there?
Is the mother o.k.? Has she been checked by the vet? I would also suspect her milk? maybe infected or contaminated?
You should have left your female for a pet...breeding dogs is not a hobby. Breeding, as you have seen puts the mother's life on the line, as well as the babies.
Lots of heartbreak.
Gina