Please give them beer in their water in their separate runs for the full day before you move them at night together and give them beer in their water the full day they are merged. The beer makes them happy, more docile
And it is difficult for them to Beat the beegeebees out of each other staggering around drunk. After that you will not need to give them beer in their water.
I learned that from Gruman in Long Island back in the 60's. And early 70's. They would give the chickens beer before they would air shoot them at A -4's to test the windshields. Animal rights stopped that. It was their argument was would you rather passengers die and they never felt a thing they had beer for breakfast. I am not from New York, just from a military family, married military and retired military. All airplane plants tested the windshields with drunken chickens back in the day. Ever know what happened to a windshield not properly tested on an aircraft coming down out of a cloud and hit a flock of birds? Death and destruction and many human lives lost. It is how I remember it from the days of yore.