Cochin is bleeding on her head

You can Super-Glue any torn places back together. Super-Glue is a really good, effective alternative to stitches. Just put antibiotic ointment on after glueing.

Maybe you could coat vulnerable places with Super-Glue, too?? Hmm--But maybe that would give the other birds an extra good grip to do more tearing?? You'd have to experiment.

Pine tar daubed on a wound can help it heal. It is gooey so it sticks to the wound. And other birds will veer away from getting the gooey nasty stuff on themselves.

Pine tar is sold for use on horses' hooves, but many people use it on chickens on wounds that are getting picked on.

Also, put obstacles around that can help her get away from the other birds. I wrote ideas of how to help with that at:

http://www.backyardchickens.com/t/594086/introducing-a-new-chicken#post_7783126

You might have to keep her with a fence between her & the others for a little bit, so she's separate from (so her injury can heal) but close to the others (so she doesn't get treated like a total newcomer when she's fully back with them..

Best wishes!

p.s. I edited my first message, so there are a couple new points there now, also.

I would try to keep her where she & the others can see each other at least part of the day if you can. If you separate chickens more than a couple days, it's almost like they're strangers to each other when you put them back together. And she'd be the lone newcomer.

Something that might be helpful that you could try, also, would be put one or two of the other chickens with her in her "recovery quarters" for a day or two right before. That way she'd have a partner "newcomer" to help dilute pestering as they rejoin the flock.