RE: Odd behaviour change: suddenly laying flat often

[Bam]

Is it very warm? They get less active when it’s warm.
I’d say it was normal if he was like 1-2 years old, because many bunnies or rather, most bunnies, do find “inner peace” as they become adults. He could be a late bloomer perhaps seeing that it is a only year since his neuter (most house buns get neutered earlier, and neutering does have a calming effect).
You will of course have to keep an eye on appetite, poop, interest in interaction with humans, interest in life around him etc. Just “resting” in a comfy sprawled-out position is not an observandum in itself. Lethargy, inappetence, actively pressing the tum against the floor are things you see in a bunny that’s not feeling well, but you know what that looks like.