When I was a kid I had a dutch doe and a large lop mix buck in a large dog kennel (with a dog box)....my parents let me raise them how i wanted and even though that's not appropriate housing for rabbits...esp a buck with a doe...that was the most sucessful rabbit raising i've ever had.
Bucks are actually very wonderful with kits to be honest..however most show rabbit breeders want their does only breeding at specific times and managing the litters, plus to keep stress levels low, so they keep rabbits in cages by th emselves only together during a quick breeding meeting.
The problem about keeping intact bucks with intact does, is fighting amung does, the buck will rebreed the doe the SAME day she kindles (gives birth)...so almost a month after the first litter she will pop outa second litter....and that's really hard on the first litter of kits because some are still nursing....
My doe had 2 large litters of kits for me (she was rebred the same day she kindled)...she raised them all up and they all grew large like their daddy...all different colors. I raised them horribly wrong....cement ground cage, dog kennel, dog box, sweet feed with no hay....that's neglect, but i didnt know anybetter (i was 13 and had no rabbit books or the internet lol). However those were the healthiest rabbits i ever raised..no illnesses, no loss of kits..no fighting..nothing.
Then when i rasied show rabbits and kept them separate fed high quality show rabbit feed, continuous supply of hay ect, i had illnesses, stress, abortions, cannabalism, aggression, infertility problems you name it.
By the way european rabbits are the wild form of todays pet rabbits...not the cotton tail of the US. Cotton tails are solitary where as europeans are conony rabbits....they have dominant rabbits and everything. So yes it is natural for the domestic rabbit to live in colonies, it's just that just like with dogs, there is dominance issues,anad rabbits can really hurt eachother. I'd honestly reccomend if you're going to colonise your rabbits makes sure hte area is big enough, and plan for litters, and plan for what you're going to do with the kits...if they will be meat rabbits, that'd be perfect....as it wiill be hard to find homes for excess, it can be hard to even give away bunnies to good homes.
yes bucks will fight and molest eachother relentlessly....i have had bucks litterally bite the testicles off of other bucks THROUGH the cage. same sex pairs can get along, but when hormones are going crazy..there is a lot of tormenting.