The only way to not get baby bunnies is to keep the two rabbits separate -at all times. It takes seconds for a male bun to impregnate a girl bun, and she will ovulate upon being mated. Rabbits dont have heat periods like dogs (you probably know this but other readers of this thread might not), so a mature girl bun can become pregnant at any time, and it can happen so fast that you dont even notice its happening.

The buns need to be kept separate not just by cage bars, because rabbits are capable of breeding through cage bars. There must be a “no man’s land” of at least a few centimeters between the buns’ cages or enclosures.

I hope you can find a way to house these rabbits separately. I understand that it’s not an easy situation.

You will need to keep them 100% separated, they can mate in a flash, even while supervised. They will try very hard to “get at” each other, so it’s very important they can’t access each other at all. Buns have also been known to mate through cage bars (somehow!).

The best thing will be to keep them separated and start saving up to get them spayed and neutered. Neutering is usually easier and cheaper, but spaying is very important to prevent reproductive cancers, so ideally both will be castrated eventually. But you can start with 1 just to prevent an accidental litter.

Can you set them up in different rooms, even if it’s not ideal? Investing in some x-pens to help separate areas would be good, make sure you get the taller ones so they can’t jump over.