I wouldn't do it either, not with a little 8 week old. Integrating a single new bird is really hard, this one is so young, it will be even harder.
LIke 7L Farms I will never again attempt to integrate a single new bird. I did it once but never again. I separated off part of the run for her, kept her in the coop in a wire dog crate at night, let her roam with them in the pasture in the afternoons. This went on for over two months, they still would not accept her in their coop/run. The final time I tried putting her in with them they nearly killed her. I nursed her back and now she just lives free in my barn with a little bantam friend.
You might try it when this young one is a little older but plan on taking your time doing it and also have a backup plan for her in case it doesn't work.