Hi there, welcome
What you’ve experienced is common, babies get along, but once they hit puberty that goes out the window.
Definitely separate them, but keep them side by side if possible. Things can escalate to full on fighting, and the more they squabble the harder it will be to re-bond them once they are spayed.
You will want to give them separate free-roam time, because you are right in that they will probably fight if out together, or invest in a couple x-pens so you can divide the space in half. Make sure to make a buffer through the fence so they can’t nip each other through the fence.
Once they are spayed, and given some time for their hormones to settle, you’ll need to go through the bonding process with them. This involves having supervised sessions in neutral space to let them safely establish their dominance hierarchy. If you’re not familiar with the bonding process, I recommend checking out the bonding section under the bunny info tab at the top for a good overview.
And of course ask more questions here
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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.