I don't know. When I want to do something, I just do it, but I sit myself down to supervise the invite. I did introduce 2 very young keets to my flock, years ago and most of them would bully them, but I had one single barred rock hen that adopted them. I had this idea that seeings that she was the only one that color and the keets were the closest thing to her colorings, that she took them in. She began standing up to any chicken that threatned the keets. I don't know about full growns. I guess they will just have to go in there and figure it out in the pecking order.
I also plan on getting guineas, but not until this spring. But I don't want to raise them with the chickens. I want to do it by the book, so I can use them in the garden, to cut my work a bit.