I just put mine together, and they do fine. giving them playdates for a while when they are freeranging helps, I have gone from 2 to 4 to 6 to 7 chickens, and it has always worked (i also may have roosters, but we aren't sure)
I would be careful, you have two roosters, merging/adding to roosters together is very hard and they will hurt each other, and the other hens...be careful.