I'm glad to hear that she has recovered enough for you to take the next step of re-integration.Wanted to give you an update on Rosie. I put her back in the outside coop today after being in ‘chicken intensive care’ for several weeks. I have her separated from the other chickens so she can become accepted again. I’m not sure how this is going to go. My other Rhode Island Red even tried to attack her through the wire that was separating them. She is so much smaller than the other hens and although she is eating and drinking and acting ‘almost’ like her old self, her cone is still paler than the others and I don’t think she’s at 100%. However, I felt I couldn’t keep her in the garage coop any longer and it was time to be back outside and just watched, closely. Hoping for the best, but still concerned.
It may take a good while and some patience to get her back into the flock. There's always a possibility that she may never be accepted, but all you can do is take one day at a time and hope for the best.
If you have space and time, letting them all out together with you monitoring them closely may or may not work. Chickens are hard to figure out at times.
You may want to read the article that @azygous wrote about integrating a single hen. There may be some tips in there for you. http://www.backyardchickens.com/a/introducing-a-single-hen-to-an-existing-flock
I hope everything goes smoothly and she is back with the others in no time.
Thank you for the update and please let us know how it goes.