For the imperialists among us (feet and inches folks) Cosima is describing a pen 3 feet by 6 feet. A nice big hutch/pen to be sure.
This MIGHT be big enough for 2 adults if they liked each other very much, and they did not breed. But this is about the size of one pen for my 8-9lb breeding does. When she has a litter of 8, even this size pen can be crowded.
For something tiny like a holland lop it might also be ok for 3 really lovey bunnies. But if they do not get along, where does the loser GO? They can't get AWAY. So you have Bossy saying "get outta my sight, or I will kill you!" and there is no place out of sight to go.
@Cosima , if you wanted to keep 3 together, ideally they would have a ridiculous amount of space--like 3m x 3m--and it would have lots of tunnels and hidey holes and places to get out of sight even then. Once they have been together a long time, like a year, with no fights, you could probably put them in a smaller space. But it would be still up to the rabbits. They have distinct personalities--just like dogs. I could put 6 dogs in a room with no problems, and then put 2 in a 1 acre yard and have them kill each other.
I am not saying it is impossible, I am saying NO ONE here wants to say "oh sure, no problem" because it absolutely can be a problem. You are not gone at work 8-9 hours a day, so you actually have a
better chance of trying this out successfully than some of us! I can't watch mine every minute and I would not want to worry constantly or come home to a rabbit with its ears in ribbons--and I HAVE once, so it is a real thing that can happen. I just want you to be successful, and this idea has a significant possibility of failure. You just need to be smart about this and be prepared for that outcome.
@hotzcatz has rabbits in semi communal housing like you are describing, and their rabbits are smaller than mine. You may want to follow them and check out their posts for ideas on how to manage that.
Editing to add: ok, 3m x3m can hold a lot more than 3 rabbits. But the point is that then if someone gets grumpy there is somewhere to run, becasue that is how a rabbit deals with conflict. Ideally they don't need to run--so the only way this works is fi you can really watch them pretty closely and watch for aggression signs before things escalate to the point of injury. I had 2 does in a 3m x 3m pen for 10 minutes and had to rescue one before it was kicked to death. I have even had them go after each other in a 10m x 20m back yard. Maybe my rabbits are antisocial or something...