I think it totally depends on the rabbits involved, the age, temperment, gender, fixed or not, personality, circumstances, etc.
I have the whole range, singles, doubles, a trio and s grieving bun who has just lost his bonded brother.
Some of mine afre definitely happy by themselves, far happier than when i have tied to bond them to someone. I have one who was snipped early Spetember that I am thinking abut bonding with someone, but it will depend on him, he sees me as his so it needs to be someone who is not so bonded to me (maybe with him, me and him make a double? lol)
my two current doubles are both sets of unfixed guys and i wont be adding anyone to them because that could easily upset a very finely balanced apple cart.
i did have a pair of does. they had to be separated back in july for some heath reaosns and they went back togethr like a dream. whwen thery were together they were basically one bunnym moving at the same time, looking at the saqme time, doing eveyrthing and anything at the same time (no jkidding, they even look the same and are virtually impossible to tell apart). when they were apart thery had developed their own peronsalities and when they wrent back togethr they vwere individuals as opposed to one giant bunny with two bodies.
I decided with those to attempt to add another, so we did some bunny dates (I have a fair few to choose form) and it seeme dto work best, strangely, with our most dominant and nasty buck. they all got on, and became really soppy together. They have only been togethr for a couple of weeks, btu they hate to be apart now. the buck is lovely with them, and only nasty with me. in this instance, having a trio seems to be currently wokring well, and the unfixed does accepted him well, and if/when one dies and they are still together, then it will be better for them to not be alone.
my grieivng guy lost his buddy last friday and its breraking my heart watching him, but he qwill be ok. he's 8 and introducing a new bun would stres shim out more. i did disucss with my mum about bringing another bunny into the pair, to make a trio, a couple of years ago, but his brother was ill so we didn't, plus it would have upset the apple cart with them aswell, fiven they were unneutered guys too.
i think the key to knwing what to do is to know your buns inside out. and whos to say it has to sotp at trios, there is always scope for more, provided it is done carefully and you REALLY know nyour bunnies.
