Thanks! He is already starting to fill out!
Yes, he should be fed about a 1/2 to 3/4 cup of puppy food 3x a day. And he should be having at least three bowel movements a day. If he is eating, and otherwise acting like a puppy, he should begin to gain weight soon, and have more bowel movements even sooner. Make sure he always has access to water, and that he drinks. You can test his hydration by pulling up on the skin at the back of his neck and letting it go: returning to normal quickly is good, slowly is not, and means he needs more water. You can give him water using a turkey baster, giving him time to swallow and not 'drowning' him. If he does not respond positively to this care, take him to the vet. Blessings - Blu