I found a specialist rabbit vet in our area, we have two mini breeds and they were successfully desexed. They did say the smaller the harder the surgery. The female wasn't eating as well as we would have liked so we took her back to the vet and they gave her critical care. We tried to give it to her but she was a handful. The specialists said that the only bunnies they lose are ones that are already sick and ones that are too old. They shouldn't really be getting desexed if this is the case ( bit hard if you don't know however).