Jasper's acting weird

He was running around the garden happily earlier and wasn't best pleased when I put him back in his hutch but never is, just been out to give him some veg and he started making like a growling grunting noise and running towards me, didn't bite but didn't keep my hand in there long enough to find out if he actually would :/

Just to add he's never been aggressive before or shown any signs that he's unhappy

How old is he and has he been neutered?

Does he have an attached run - it sounds like he enjoys his running about time so giving him a bigger run he can access all the time might help is he's feeling frustrated. I guess they don't really understand why we shut them back in while they are busy having fun.