I would probably start to decrease the vitamin b everyday little by little, as long as she recovering well, your on the right track. If she's been inside I would not just let her loose to the others, i would have her in a cage so the others can see her but not be able to harm her, you want to introduce her back into flock slowly, others wise they may start miss treating her and she'll be back in the house with more injuries.. I would treat her as if she was a new chicken that you just got, take it slow with her and gradually let her back out. See how things are one day then the next and when it looks like they aren't going to peck or bother her you should be good to go..