Hi there

You’ve certainly done the right thing by having them both neutered, as a general rule rabbits cannot be bonded without both in the pair being desexed. I have heard of very few exceptions, so you’re certainly on the right track.

How long has it been since they were both neutered? Usually a minimum of 6 weeks post neuter is recommended before starting re-introductions because it can take a long time for all the hormones to leave their system. Sometimes there is also what’s known as the post spay/neuter craze, where hormone driven behaviour gets worse for a time before it gets better. And as with anything, some will take longer to calm down after a neuter than others.

For now, you need to keep them separated as you are doing. It is recommend to do pre-bonding which includes swapping toys, blankets bowls between cages and also swapping the cage that they are in. This is to get them used to each other’s scents being in their area, and not have a set area of their own. Since your boys have a history of fighting, you’ll likely need to take it slower than normal since there is ingrained responses there already as to how to act when they encounter each other. When you do start reintroductions, you need to do it in a neutral area where neither rabbit has ever been. In a situation like this, I’d suggest keeping the dates as short as possible to begin with. I’m talking one minute at a time. Roll up a towel to act as a barrier between them, have one each side of it and just pet them for one minute and then remove them from the situation. You always want to try to end bonding on a positive note, so if you can only get 30 seconds in before they’re out of control, only have them meet for 20 seconds. In theory as they become more comfortable, you can slowly extend the time they are together and remove the towel barrier between them, followed by sessions where they are allowed to move around freely in confined space. Gloves and a dustpan are recommend for breaking up fights so that you can avoid being bitten.

I didn’t know it had a name, lol. But I believe it is the smoosh technique, yes. I just figure rather than putting them in an area and seeing how they’ll go for a short date (like most bonding) you already know what will happen there so better to try and control the outcome

I would also swap litter boxes, yes. Could make for a little bit of a mess, but it should help