will my flock know to go into the coop with the other chickens at night?
You are dealing with living animals. No one can tell you for sure what will happen. Each chicken is an individual, each flock has its own dynamics. We all have our own experiences, set-ups. conditions, goals, and management techniques. We can tell you what we think might happen but each time is a unique experience even if we think conditions are identical. I will mention that when the others take ownership of them they have the responsibility and control. That can be hard for some people to accept. One of my best friends is like that. That does not make her a bad or weak person.
I don't know what the new facilities look like or how they plan on handling integration. Dad free-ranged his chickens, a mature rooster, many mature hens, and often juveniles of various ages. When he added new chickens, usually chicks younger than yours, he took them to outside the henhouse and turned them loose. That was about it for his hands-on integration. If he did not like where they were sleeping at night he'd move them but that seldom happened. Most of the mature flock slept in the henhouse but some slept in trees. He was OK with that.
Yours are 6 months old, the others are 9 months. I'd expect them to maintain two separate flocks for a while. As I said, this may not happen. As yours mature they will merge more.
I have no idea what techniques the new owners will use. If they go through housing them they can train them where to sleep. If they just let them go like Dad would have they may follow the others into the coop to sleep or they may not.
Breed and age makes no difference...it's about territory.
We have our own theories about that. I agree that breed does not matter. Technically age and maturity are different things but they are related. I think maturity can make a big difference in how they interact. At 6 months I don't know how mature yours are. In my flock the more mature tend to outrank the less mature and many aren't that shy about enforcing pecking order rights. If course there are exceptions to this, plenty of times I've seen pretty young chicks leave the protection of a broody hen and mingle with other adults without problems. I often have adults and two or three groups of differently aged juveniles in with them, some juveniles broody-raised and some brooder-raised. They may mingle some, especially some juveniles, but they each tend to form sub-flocks and keep to themselves. During the day they spread out. At night the adults sleep on the main roosts, the older juveniles sleep on my juvenile roost, and younger juvenile sub-flocks sleep in their own corner on the coop floor.
I'm not sure what you mean by "territory". If my adults are hanging out under my mulberry tree that is their territory and the juveniles generally leave them alone. If the adults are under a plum tree that is their territory and the juveniles are fine under the mulberry tree. If you mean territory to be wherever they happen to be OK, but that's why I often mention personal space instead of talking about territory.
There can be another meaning to this. Sometimes chickens or maybe one specific chicken will attack any strange chicken they see. They know their flock members and for whatever reason (there can be different reasons) they don't want any strange chicken in that area. This attack is usually not to kill but just to run them off. If they have enough room where they can stay separated, like free ranging, this shouldn't be a problem. If they are kept within fences it can be.
@Sherri1990 it sounds like yours are going to a great life. With all that space things should go really well as far as integration. If they are free ranging predators probably aren't a big problem. Anything can happen but the only question that would be bothering me about behaviors would be where will they sleep. That can be managed. I know you are attached but it really is up to the new owners.
