Bonded rabbits will only occur after the parties have been fixed. EDIT: There are cases of unfixed male pairs, but that’s very dicey and dependent on personality. Personally, I don’t think it’s worth the risk.
Currently, you have 4 rabbits who happen to get along because they do not feel their hormones hit. Young rabbits will get along with anyone really. Getting them neutered will not break bonds because they are not established yet. Neutering will lay the foundation for the bonds to be created. I know it seems odd because you may see them grooming and cuddling now, but again, it’s because they’re young.
They ALL need to be neutered if you’re keeping them all. Think of their relationships as gears, turning together. Hormones are like a spike going into the gears. Once it’s there, getting the wheels to turn is not possible due to territorial instincts, mating frustrations, etc. You should separate all four rabbits from each other. If you’re not going to neuter them, it needs to be permanent separation to prevent fights (which can break out overnight, even if they seem cuddly and happy during the day).
Also, unless you see testicles on every rabbit, it’s highly possible one or multiple are actually females. Sexing young rabbits is a gamble most times. Regardless of experience, I’d say 1/3 of people are told the wrong sex because the anatomy is so small.
Bonding aside, neutering will allow your rabbit to be a pet, not driving and frustrated by its natural instincts. It’s important to have it done eventually.
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.