I bought 6 guinea keets from a local farm and kept them in a cage on grass till they were 6 weeks old (moving them inside to a heated place at night). At 6 weeks I moved them to a bigger cage until they were 3 months. After that they've been left to free-range. After a few days of me trying to "get" them to roost high on trees or fence, etc., they started roosting in the henhouse with the hens. I couldn't really stop them from that although I worry that their loud chirping keeps the hens up at night.
Mine never fly high, and I've wondered if somehow I "taught" them not to fly since their cage wasn't very tall - 2-3 feet high for the first 3 months of life. They seem to get along fine with the chickens, although they keep to themselves when they free range, and yes, they behave very differently. Very group-oriented. They don't range any farther than my chickens though. I had wanted them to sleep in the trees as friendly "watchdogs" but they chose to be in the henhouse so they're not exactly the watchdogs I wanted! Their noise DOES get annoying, just a warning!
One of mine was attacked by a dog last fall and I thought he was a goner, but I kept him in a hospital pen for 3 days and after that he recuperated 100% and is out with the rest.
Best of luck with yours!