Taste of the Wild! Yes! That's what I meant to write. I don't know why I said Call of the Wild?! lolol...
It really depends. I believe it is possible to feed both kibble and raw together. I know a fair number of AKC breeders that feed their pregnant females raw and cooked meats to supplement on top of kibble. I know its not for every dog. Some dogs are more sensitive to change than others. But I've had a good experience with it. But then again, my dog seems to have an iron stomach compared to others I've seen...(she eats everything. literally)
However, I can see how it could upset a stomach if the dog was on a certain kibble and only that one type of kibble during it's entire life then suddenly ate raw. Most dogs aren't like that though. Lots of dogs are given more than one kind of food to eat throughout their day or life. And if you start both types of food, kibble/raw, young, it wouldn't be any sort of problem.
Dogs are a lot more resilient than you describe.