Well that is a great start, fantastic. He is still just a baby, so to have coped so well with such a big change is fantastic. As or skinny, yes, he will be a bit of a whippet at this age, they do tend to be lean, more so than the show cocker. As for food, I feed Daisy RAW, it really suits her, tried a few other options with her and she has settled on Honey's Real Dog Food. I bought a small chest freezer so I can order a few months worth at a time. Lots of options out there, and when you both get settled, you will probably want to have a rethink. For now, fantastic news, and a few baths/showers will soon have the kennel smell away.