Having integrated chicks "the old fashioned way" of waiting until they are 12 weeks or older, versus integrating chicks when they are little (I like to wait till they are off heat at 4 - 5 weeks old, but have integrated up to 8 - 9 weeks old also. IMO, it works much better when they are younger, before they approach sexual maturity. Integrate them while they are still "peeps" before they start to get their "cluck". (before their voice starts to change) At the younger age, they are not considered to be a threat to the pecking order. The older birds will give them a few lessons re: obeying their elders, but it does not become the struggle that is seen when they are sexually mature. No matter when you are integrating, IMO, it's essential to do so with plenty of room in the coop and run, plenty of feeding stations. If possible make the first meetings occur when they are out ranging in the yard. And give them treats to distract them when those first supervised meetings take place.
