help!

[Kasey890]

I am a first time chicken owner. I have 8 chickens in a very well made coop by my husband (thanks to a design on this page). They have a nice outdoor run area. They are 9 month old chickens (combo of red stars, americauna and australops). For about two months we have had a problem with a bully hen but have been unable to pick her out of the crowd: one by one all of our hens are developing bare backs. Today I went out to my coop to collect eggs and it looked like a chicken massacre. I was instantly terrified on what I would found and thankfully it was not as bad as it looked. One of my australops had a torn comb and broken beak...needless to say she was bleeding pretty badly and likely was attacked.
I removed her instantly and placed her in a safe place. Provided her with food and water and plan to keep her seperated for a few days to let her heal. I spent time with my birds and looked at each of them closely to find I had only 1 hen without a bare back. To my surprise she was my smallest red star. I have friends who have chickens and they immediately offered to rehome her and give her a second shot.
Now my questions are these:
I have 7 hens with bare backs---some more severe then others. I live in MN and it's cold. Will the feathers grow back on their own? Do I need to put something on them to heal them? There are no major open areas that I can see?
Is this a behavior the whole flock has likely picked up or by getting rid of the problem hen maybe I have solved my problem?
My bird that was injured looks to otherwise be in good spirits --I have her in a dog kennel in my heated garage with food and water / hay . Do I need to do anything else special for her or do I just let her heal?
When re introducing her do I just stick her on the roost in the middle of the night?
Sorry for the million questions. I had a slight panic this evening

I have attached a picture of her back which is by far the worst out of the group.

 

[Firekin1]

Feathers will grow back just fine, your seperate hen should heal on her own as long as you make sure she's eating and drinking well as a broken beak can be painful for a bit, after shes healed up enough you'll have to re intoduce her slowly, for example putting her where the others can see her but not reach her for a week or so, and even after there still may be some kerfuffles to re establish the pecking order which looks worse than what it is. Make sure your hens have plenty of room in the coop as over crowding can be an issue and cause fighting because they are competing for space.

 

[Kasey890]

Feathers will grow back just fine, your seperate hen should heal on her own as long as you make sure she's eating and drinking well as a broken beak can be painful for a bit, after shes healed up enough you'll have to re intoduce her slowly, for example putting her where the others can see her but not reach her for a week or so, and even after there still may be some kerfuffles to re establish the pecking order which looks worse than what it is. Make sure your hens have plenty of room in the coop as over crowding can be an issue and cause fighting because they are competing for space.

 

[Kasey890]

I've read a lot about blue kote? Should I put that on their backs ?

 

[Firekin1]

Blu kote is an antiseptic...unless their bare spots are bleeding or raw (which they would be attracted to pecking at those bloody spots) there's no need to use it as it would just dye their skin blueish a few days.