I'm sorry your baby isn't feeling well. Is he over the reaction to the vaccines?
I agree with trying the boiled skinless chicken. I'm not sure where you are in town, but there are quite a few small pet food shops around here that sell the higher quality kibble and canned food. We've been using Natures Variety kibble and canned with great success, all 5 of my dogs love the variety and the taste.
Another thing you might try is to hand feed him the kibble or anything to get him to eat. It's good that you are staying in contact with his breeder and your vet, always the first calls you should make
The nutrical can stimulate them to eat as well. I wouldn't give him the ceasers, this isn't a quality food.