I think she'll probably recover with treatment, although it's hard to say what she'll have for tail feathers later on.
I would be very concerned about putting her back in. Please don't try to put her back in unless it's a time when you can be available to save her again. When attacks go this far, the flock dynamics are sometimes such that the victim can never be successfully reintegrated into the flock.
If you can reintegrate her, that would be wonderful. If you can't, she might do very well in a different flock, with more gentle companions.
I hope this works out for both of you. Faverolles are so sweet.
I would be very concerned about putting her back in. Please don't try to put her back in unless it's a time when you can be available to save her again. When attacks go this far, the flock dynamics are sometimes such that the victim can never be successfully reintegrated into the flock.
If you can reintegrate her, that would be wonderful. If you can't, she might do very well in a different flock, with more gentle companions.
I hope this works out for both of you. Faverolles are so sweet.