Would you consider putting a 'topper" on his food? Like cottage cheese, yogurt, or some sweet potato ( ifhe is not allergic). Sometimes dogs just get "tired" of the same old thing. I also make homemade meatballs ( good ground beef, brown rice, eggs and frozen veggies) and add one to Bogey's dinner kibble. He gets a scrambled egg over his breakfast kibble. He loves it. Not a morsel left! Also, does this just happen at dinner? Is he eating his breakfast ok? Bogey is 6 months and is on 2 meals a day with a snack at lunchtime ( a little yogurt or cottage cheese. No kibble at that time) You could also try a little low sodium beef broth too. Good luck!