2 female rabbits cuddle up together but have started chasing and mounting each other

Hello!

I'm new to this forum and would like some advice please. We bought 2 female rabbits at the beginning of September off someone who had them for a couple of months. I think they said they were born about April time and are sisters. They've always got along well but over the past week they seem to be chasing each other and mounting each other. I've checked them both and there are definitely no boy "bits" and from what I've read online it seems to be a common thing of one rabbit trying to show their dominance over the other.

They will sit up close next to each other and occasionally groom each other but have spent a lot of time today chasing each other round, nibbling each other's back then mounting each other. One of the rabbits seems to be more dominant but then the other one must get fed up with her as she then has her turn chasing her back. Will they just grow out of this or will it just continue and I should separate them? We've only got one hutch although there is an upstairs/downstairs so I could close the top bit off but then the upstairs rabbit wouldn't have access to the run.

Would spaying them stop all this or would it just continue? I hope someone can help please!

Many thanks

It's very common in unspayed rabbits, I had 2 sisters who did this, I had them spayed as soon as they started it, and managed to keep them together. You will need to watch them very carefully and if it escalates into nipping, circling or fighting you will need to separate them until 6 weeks post spay, after which time it may be possible to rebond them in a neutral space.

Spaying should help dramatically and would be the best option to get it done asap to prevent against any injury.

As said, it takes around 6 weeks for hormones to settle so I'd monitor very closely if you decide to keep them together for any signs of real fighting (biting to cause injury, rolling on floor together, boxing, circling).
I've two unrelated females who are both spayed and we still occasionally get humping, chasing & fur pulling but it doesn't escalate so we don't worry about it. Before being spayed they'd fight to cause injury (they were around 12 - 14 weeks when doing bonding so both were spayed really young).