If you are looking to get just one chicken, then look for one you can introduce to yours. I had to go through all the extra work raising the single chick, and introducing a single. Once after the chick was able to generate her own temperature, things did get easier. Then after letting her stay with the adults I had to be there to stop fights. Over a few weeks they learned to tolerate each other, and now the new chick is able to roost on their favorite stick.
A thing about the stick is they like the spot in the cage. Even when I removed the stick, they still roosted in that spot on the ground even in rain and snow. So the new chick being allowed to sleep there at night is a good sign.
So keep in mind raising a chick separate from the adults requires more work and you're going to have to monitor them all day and in the evening after introduction.