I had a thought about hens getting along. when I bought my first 3 hens I got them from a farm but they were all different breeds, I did this so my grandchildren could name them.
Any way, they were put in a box together for the journey home which took around 30-40 minutes, then once home I put them in a small coop I had and that was their home for 3 days.
then I released them in to the garden to free range, the thing is I never witnessed any fighting but may be that was done in the coop but they all seemed to get along.
So moving on a few weeks I decided to get 2 more from the same farm, again put in a box together for the journey home, I put them in the small coop together for 3 days but let the others see them in their little run.
The new 2 were different breeds but again they were like sisters, on release to the other 3 birds a bit of squabbling took place but nothing serious, the original 3 seemed to stay together and new 2 seemed to stay together, but on time mixed in together.
There was a bit of squabbling at roost time the 2 new girls were last to go in and I witnessed a bit of pecking going on, obviously letting them know they were the lowest rank. As time went on one of the original girls got a leg injury and had to be put down, I think this altered the pecking order a bit too.
Sorry for the long story to get to my point and that is I think the journey home in the box together did something to form a bond, because this was their first ever journey in a car and they were all nervous, so in my mind they had each other for support.
Again this I think happened to the 2 new girls, they bonded in the box and car journey home, I know I only have a small flock so it was easy for me to do, but I often wonder if you get 2 or three that don't get along put them in a box together and take them for a ride and see if they are OK when you get them back home, it might just work.
Also the box was a cardboard type with just a few breather holes so it wasn't exactly dark but more confined if you get my meaning, not a dog crate, this too might make a difference.