Welcome to my world. Usko has always been picky to the point of me losing my mind! I fed him kibble in the beginning and tried to spice it up with anything and everything possible. That is the first reason why I switched to raw and he does eat it more willingly but still not all and not everytime. Maybe you could try wet food if not raw for him??? I would also try giving him some vitamins and minerals if he is not eating as much as he should. I still sometimes give Usko Nutri Plus gel if he hasn't been eating.
I'm sure that Uskos front paws turn to the sides cause he didn't eat and get all the nutrients growing up, not cause he got too much protein.
Also if he is motivated by food and treats when training, like Usko is, you could give his food as training treats. The trainer that we use said why should dogs eat their food from a bowl??? And as an added bonus you get a smart dog.
I wish I'd have some magic trick or pill for you that would make him eat, but I'm still looking myself. I'll let you know as soon as I find it....