If it only is when he is snoozing, it could be snoring. I’d say observe closely. If a bun has a congested nose, youd hear it extra when he is excited or active, for example after running around.
It is normal for buns to want a certain veg very much for a while and then, suddenly, get fed up with it. It is as if they get enough of the particular nutrients in that particular veg- or r if it is some special chemical compound in the plant that their instincts tell them they dont need more of. Wait a week, then offer the same veg again, and the bun, as a rule, will want it again. I’ve seen this very often with my buns and wondered what it’s all about. It’s best if you can rotate greens, and that works best if you buy greens that the humans in the family likes too -that way you dont have to let greens go to waste.
I hope you’ll get your hay soon! As Dana says, it is the most important food for a bun, and it is what keeps the poop round and, ideally, almost golden.