Canis-Lupis you said; "I hand reared two pups of our Mists from a large litter and they went back with the others after about 3 and a half weeks and did just fine from there on."

Did you actually raise the pups without any contact with their mom or littermates for 3 1/2 weeks? If that's the case, I'm curious about the events that led to such an unusual decision.

Usually in large litters, even if it's necessary to supplement the mother's milk, all of the puppies are left together between feedings so they can be raised in as normal a setting as possible.