Lots of dogs do fine with a diet of just dry kibble. I take the recommended amounts on the package as just that, recommendations. If he looks thin, give him more food. If he looks too fat, give him less food. (My dogs usually eat less than the recommended amounts.) A very young puppy might benefit from having their kibble softened, so that it's easier for them to chew, but if they are able to crunch it up, they should be okay.