we have a old coop with 10 birds in it and one rooster. we have built a new coop and have our new birds in that there is I think 15 birds and 3 roosters. we want to mix them togeter in the new coop. I have free ranged them over summer togeter and very little fights. the older hens have already establesed a pecking order but I am unsure how to introduce them to the same coop, I know I should do this at night any other Ideas?