
If he likes wet food then that's the way to go If he likes chicken then adding that will encourage him. you can chop it up quite small & mix it in well so he has to eat all the food to get the chicken. His hindquarters should fill out as he matures & puts on muscle.
I always have some B Sorb in(well did just given mine to a friend whose Rough Collie wouldn't eat to get him strated which it did) I know Tohme can suggest a mix that will encourage dogs to eat which I think includes Brewers Yeast Hopefully she will see this & add her comments
I get my chicken from an organic source,but any british chicken can be used & the juice used to either soak the kibble or food(not the neat fat though) I put the pieces in water & cook gently until the meat falls off the bone & then chop it up & freeze it in a couple of days portion sizes.