New to chickens and first injury, please help!

[truchicks]

I have 4 - 7 week old chicks that have been together since day 1. The Salmon Favorelle has always stayed away from the other 3 and I just thought she liked to do her own thing. Well, I just went to check on them and her back is completely bare and bloody. She wasn't like this a few hours ago.
This is a pic I took after I cleaned her back off with some Vetericyn. What should I do? Can they pluck that many feathers out that quickly? This is my first disturbance in my small flock and I'm not sure what to do...any help or advice would be greatly appreciated! Hope everyone is having a Happy 4th!!

 

[Eggcessive]

Salmon faverolles can be meek and usually rank low in the pecking order. Mine have always been pushed around by other breeds. Make sure they have plenty of room, are getting a 20% balanced chick grower feed, and it can help to let them outside daily. Supervise them while they are out to watch for bullies. Some use BluKote spray or Nustock Cream on bare spots to hide them, and help heal. They are already forming their pecking order, so hopefully they will work it out. Make sure you have 2 feeders and waterers to everyone gets a chance.

 

[truchicks]

So , I think I'm dealing with a bully and separated the Australorp from the rest of the flock. The SF is still not being accepted by the SS and the LO...how should I deal with this? You can see the S. F. laying on the outside of the coop, while the L.O. and S.S. are cuddled up together in the dust bath pan inside the coop. I feel bad for her but I don't understand chicken psychology and I am not sure what is going on here. Anyone???