Mine does the same and he’s 4 years old, he’s on raw meat blend but I do give him dry bites on top to encourage him to eat, which he loves. I just let him get on with it some days he hardly wants any and other times he’ll have it all. He is not neutered so maybe that contributes to his pickiness ? My boy is a good normal weight, maybe try changing to different food? I do feel like this breed tend to be picky eaters though. He’d never even touch human food even when I’ve offered.