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.
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The answers provided in this discussion are for general guideline purposes only. The information is not intended to diagnose or treat your pet. Seek the advice of your veterinarian or a qualified behaviorist.