Actually there is tge possibilty of hormonal surges and puberty-like behavioral issues any time in an intact bun’s life. But grumpiness is also a wellknown “side-effect” of a heavy molt.

I had haf my Bam for a whole year, and he was a fully grown adult whhen I got him, when he suddenly went into “puberty”. He developped an obsessive crush on my dog and began pee- and poop marking. No aggression, but intense courtship of my (less than amused) GSD. It went on relentlessly for a couple of months, then I had him neutered and after 2 weeks, he was back to his old self.

Some intact male single buns never exhibit any hormonally driven behaviors. Some neutered male bunnies get hormonal in early spring (“March hare syndrome”), because light controls many hormones, not just testosterone (and there is some little bit of testosterone production by the adrenal glands). It’s very complex and not 100% understood.

Is he eating, drinking and pooping like he should?

Two of my boys are currently moulting as well. Bombur, my bunny who hates human attention, has been demanding cuddles and pets all day long. My Blue, who loves human attention, has been ignoring me on and off, and kicks his feet at me if I pet him for more than a few seconds. When my third, Badger, moults, he usually just gets a surge of energy and runs around his pen more often. Moulting, for my three, can last anywhere from a few days up to two weeks depending. Its both funny and mildly frustrating, lol.

Since your boy isnt neutered, that very well could be making this all ‘worse’ since hes not just uncomfortable from moulting, hes also uncomfortable from his hormonal surge.