Hi Sally
Sorry, from your post it just read as if he was on 2 meals a day. I dont really know what to suggest as really complete feeds shouldnt have much added to them - as Sally said it can make for a picky eater.
I've never had a breed larger than a Rott but at 10 weeks 2 lb of raw meat a day sounds a lot - I'd give your breeder a wee ring and ask them what they think is the best way forward - they'll be the most knowledgable about the breed. You need to get the balance right where he is growing nice and steady and not packing on too much weight on those young joints
