
If he is a pet store pup, he may well have been taken from his mother very young shipped across diatances, and mixed with other pups not from his litter, reared poorlythat is why you have a sickly pup.
As you may have gathered from reading this board any breder worth the name would no more dream of allowing one of their precious pups to be sold through a pet store, than selling one of their own children.
I would take anything the pet store said about the pup with a great pinch of salt.
Your veterinarian is right in some respects in advocating Dog Food, as few pet owners understand nutrional principles sufficently to feed a properly balnced mixed diet. Meat alone will be very unbabalnced and not lead to a healthy pup.
With feeding there are basically fur ways to go.
Dry complete, Wet Complete, meat and mixer biscuit *the biscuit having vitamins etc that the meat lacks), and the Raw Food diet, or as many call it BARF.
he latter has to be studied, and reading a book on the principles, and practicalities is needed.
It must also be remembered that a Peke is of an extreme conformnation, and mouth structure, and may be unable to manage to chomp raw meaty bones as easily as some, but they can be minced.
Try putting the initials BARF into a search engine.
What the pup needs now is highly digestible high quality food. Have you tried scrambled eggs to temp him. Are you soaking the dry puppy food?