Hi,
When I got my 2 female rabbits they were together as a pair and were only 15 weeks old. They were not sisters and are 2 completely different breeds. They were absolutely fine until Dotty started getting hormonal and they had a big fight. They were separated for about 4 months whilst we got them spayed and let their hormones settle down. we then started to try and rebond them.
It was a very hard process and very stressful. We had them in the kitchen and slept in the lounge for days. We thought they were getting on really well so moved them to their new shared accommodation. this potential upset the bond again so the one morning I went out and they had obviously had a shuffle and B had an injury to her ear. I bathed it and treated it and then kept a really close eye on them for days and throughout the night and they seemed absolutely fine. This was the hardest part as I was worried that B had been injured and I didn't want either of them to be really hurt but I didn't want to have got this far and then separated them again. Touch wood since then they have been okay. (I don't want to tempt fate but its been about 5 weeks that they've been back together now and they are always together. Sleeping together, eating together, grooming each other etc.
It was hard but 100% worth it. I think sometimes they need to have the chance to sort out the pecking order between them without us interfering every time (which s really hard and something I really struggled with )