It is very likely his age. How old is he again? Misha's a chowhound and even he went through an extremely picky stage for a couple months. He is better now, though I've mainly switched to afternoon and evening meals for him as he's weird in the morning. Usually even when he was being picky, he was willing to eat if things were slightly new and interesting. Like if he didn't want to eat chunks of pork, he would happily eat it if it was ground pork because that was different. A lot of dogs go through this stage. In my head, I've made sense of it as a stage where growth slows, and their appetite changes as a result of this because they're no longer desperate for calories to convert to growth. Sometimes you just need to skip a few meals. But really, how can you blame them? How would you feel eating the same meal every day? I see nothing wrong with changing it up. Add some chicken broth, kefir, or something else tasty. Rotate brands if you feed kibble. Make mealtimes fun again. But don't put too much effort into persuading them to eat the food in front of them if they don't want to. I think that leads to attention seeking self starvation.
Anyway, a lot of retrievers are that way because they have a mutation in their POMC gene that makes them feel perpetually hungry. And that makes me sad. 😢
