on the puppy chow. I wouldn't eat it either, I think you have a smart puppy! In all seriousness, I agree this is a stressful time for your pup, but it's important to get something into him at this young age. Try a bit of pedialite maybe just to get fluids into him. The pumpkin is good for his runs. I do think if you leave a bit of boiled chicken in broth out he may take it when it's quiet around him.
Now back to the puppy chow.... So full of corn, which dogs can't digest. You really should search out a grain free type of food that is appropriate to the size of your dog (will he be a giant dog, or a smaller breed?). If you decide to switch to a much healthier brand (it would be hard to pick a worse one in my opinion) mix it with the puppy chow for a good week. 75/25 puppy chow the first day or two, then 50/50 for a couple days,..... until it's entirely new food.
Good luck with your new puppy. If he doesn't start eating soon I'd be calling the vet and asking what to try next.