If she's a hen, I'm going to say that integration may be a problem, because hens are bullies to other hens. I would not bring home a hen and expect her to get along with a flock of larger hens unless you have a lot of space and tolerant hens.
However, when I was a kid, we had a pair of bantam roosters that free-ranged with the standard flock. They all got along very well, and those hens were absolute bullies. Hens usually like roosters, in my experience.
And as for the "Marek's risk"--well, you very likely already have it. And if you really want to avoid it, you can buy the vaccine and vaccinate your chickens yourself.
http://www.shagbarkbantams.com/mareks-disease/
I have added chickens from other farms to my flocks and have never had a problem with them. If you do decide to do this, isolate the little chicken for a while, then give her a "buddy" of your nicest chicken, and see if that works out. Once they've bonded, add the pair to your flock.
EDT: by "problem with them" I mean that my flock never contracted odd diseases within the first couple months after addition. I have had some trouble with Mareks, but that was always in young birds that had been exposed to the older flock too soon.
However, when I was a kid, we had a pair of bantam roosters that free-ranged with the standard flock. They all got along very well, and those hens were absolute bullies. Hens usually like roosters, in my experience.
And as for the "Marek's risk"--well, you very likely already have it. And if you really want to avoid it, you can buy the vaccine and vaccinate your chickens yourself.
http://www.shagbarkbantams.com/mareks-disease/
I have added chickens from other farms to my flocks and have never had a problem with them. If you do decide to do this, isolate the little chicken for a while, then give her a "buddy" of your nicest chicken, and see if that works out. Once they've bonded, add the pair to your flock.
EDT: by "problem with them" I mean that my flock never contracted odd diseases within the first couple months after addition. I have had some trouble with Mareks, but that was always in young birds that had been exposed to the older flock too soon.