[jaykay]

Oh, this happened to a chook of a friend's once.

The good new is she recovered 

I second Sudocrem for keeping the back moist and mending. Quiet, warm and rest will do the trick, if anything will now she's had her painkillers and antibiotics.

Don't put her in with the others til she's really mended and back on her feet, as there'll be a bit of a 'scrap' as she'll have gone right down to the bottom of the pecking order and she will need to be right to deal with that.