I raise several hundred guinea keets every year, I have about five or six hens and ten males and they all get along great. I collect all their eggs and keep four incubators going all summer hatching about ten days apart. The hatchlings go into a box with food and water covered with a 40 watt light, then about a week later into a two foot by two foot by two foot open top wooden box with a domed light with 40 watt bulb for another week, then outside into a two foot by three foot by two foot high wire cage with a light but under a roof to keep them dry. You do not want to let the chicks get wet until they are six weeks old+ and fully feathered or they will perish from hyperthermia.
In the fifth week they get moved into a two by four by two foot high wire cage and out into the yard so they can associate with the adults when they are out, just have to watch out for rain if they do not have all their feathers yet and be prepared to put a cover over the pen if it rains.
The wood box and the wire cages all have a frame that allows them to sit an inch and a half off the floor which allows for newspaper on cardboard to be placed under them for easy cleaning. At this point they are about six weeks and I move them into a large brooder pen attached to a sixteen by twenty four foot all wire cage/pen with metal roof. Then again about seven weeks into the large pen.
My point is after the first batch there are a dozen plus batches added and currently I am adding seven week old chicks in with twelve week old+ and as long as they can see each other for a few days and get to know one another I have yet to have any issues. This will continue for another four weeks until the hens quit laying (they are already slowing down laying).
This all said DO NOT put young into a pen with adults unless it is in a separate pen and let them out only when they are old enough to defend themselves or the adults will harass them to death. I tried this once and left the small cage door open with twelve week old chicks and eventually they all assimilated except one which could not handle the stress. One year later they are all best buddies but it took a lot of time and fighting to get there.
Normally I would recommend to anyone putting new chicks or even three month olds outside or moving them to new location to keep them in the new pen for six weeks so they know where home is before allowing them to free range or they may go wild or in search of their original home, this has happened to some of the people I have sold birds to when they just took them home and let them out.
It seems that since you spend so much time with your birds they know where home is but at about twelve weeks they may try to start roosting in the nearby trees if you do not get them up before dark, keep them on a regular schedule for the first three to five months and from there on they will always be in the pen when you come home no matter how late it is and all you will have to do is close the door.
