Bunny likes his new cage too much!

Two weeks ago, my partner and I adopted a 1.5 year old Netherland Dwarf bunny we named Benson. Benson came with a small triangular cage which we used for the first two weeks.
Benson spends the day in his cage whilst we are both at work, and in the evenings he has free run of our lounge room with us. He would be excited for us to come home and when we opened the door to his cage he would come straight out, only ever returning to go to his litter tray or access his food/water.
On the weekend, we purchased him a larger, two story cage. He now does not want to leave the cage. As soon as we open the door he doesn't move, and when we pick him up and take him out, he goes straight back into the cage. He is like a different rabbit!
Previously he would sit on the couch with us, and roam around the room investigating everything. We tried to close the cage door when we had him out but he kept going towards the cage and trying to figure out a way to get back in.
Does anyone have any suggestions on what we can do to encourage him to be more social with us like we was previously? He has been in the new cage for 3 nights now. We are contemplating selling the new one we just purchased and using his old small one again, however we are concerned that he will be negative towards going back to the smaller cage.

That's quite unusual. Did you rearrange anything else in the room when you put the bigger cage in? Do you have toys and boxes and tunnels for him to hide in outside of the cage for when he comes out? If not, I suggest adding some and perhaps try to coax him out with his favourite treat.

It seems very strange to me that he would suddenly not want to run around. Is he acting normally otherwise, eating/drinking/pooping well?

Like Azerane said try to encourage him out with a few toys or treats and make sure he is eating, drinking and pooping well as there could be many reasons he doesn't want to come out

Nothing else has changed in the house. He simply now has more room. Two stories instead of one.

He just sits and sleeps in the top section and doesn't use his bed. He is still pooping and goes downstairs to eat greens and drink then back upstairs.

He now grunts if we try and pick him up and when he does venture outside the enclosure it is short lived before he is back in the top section. His litter box is in the top dark room area and he sometimes sleeps in that instead of the hay which lines the floor on both levels or his bed downstairs.

It seems each day he gets a little more Ferrell and less socialised since the new enclosure.

We are now considering returning to the original enclosure he came with...Any suggestion and guidance is very much appreciated!

Is he neutered? Seems like a case of territorial aggression, where the first cage wasn't good enough so he was constantly looking for new territory, but the second cage is great and he loves it so he's establishing his territorial claim on it.

He's desexed and vaccinated. If its territorial aggression will he be like this permanently or will he be okay outside the cage once he feels it's been claimed as his?

Hm, I was thinking he wasn't neutered, a fixed bun shouldn't show such a degree of territorial behaviour. One possibility is there's something about the room he's in that makes him feel insecure and like he needs to hide. Chemical smells in the carpet maybe, if you've had it treated recently? Other animals marking in the vicinity?

Or he's sick, and doesn't feel well enough to venture outside of his safe zone much. Could you take him out, put him as far away from his cage as you can, and see what he does? Like if he's lethargic and just looks for a nearby nook to sit in, he's probably unwell. If he's healthy, active and just races back to his cage, then I'd suspect something about the outside environment is less pleasant than his cage. It is very weird, and I'd consider moving his cage to another room to see if he'd be more comfortable there.

The only other thing I can think of is what flooring do you have? Slippery hardwood/tile/lino can be very hard for a bunny to walk on because their feet are furry and can't gain traction. So he could be staying in his cage to minimise the stress on his legs. Throwing down rugs/towels would solve this.

Oh, I just saw he's only been with you 2 weeks! I'd expect a bunny to be shy and hidey the first month they're in a new home. If all the other possibilities I mentioned above aren't it, then I'd just chalk it up to new-home jitters. He's now got a suitable cage to snug in and spy on the world outside until he feels secure enough to come out and explore. Just give him time, keep things calm and non-threatening, he'll adjust sooner or later. You did good getting him a deluxe bunny condo, don't ever think that was a mistake.

Thanks for the replies everyone! We'll just see how he settles in for a few more weeks...

One thing to note--read up on rabbit behavior and make sure he understands you're the alpha in the relationship. I know of a lot of people that have been very well trained by their bunnies which is not the proper way to do things.

Hi Nancy, looking at his behaviour lately I think you're probably on the right track. Two days ago he started popping and peeing on the couch which is another new activity we want to stop. I've had a look around but a lot of what I find is about housing, feeding and getting a shy rabbit to come out of the cage. Can you please point me in the right direction for how to let him know I am the alpha as you say?