Feathers plucked by others!
My suggestions are Blu Kote or a hen saddle. This will discourage the other hens from continuing to peck at the bloody areas. I would also look at the boredom level of the hens. Give them something else to peck at like an apple hanging from a small rope in the run. You can use what is called a screw eye to secure the apple to the rope.
Diet needs to be looked at too since some will peck at feathers if treats are high and protein in layer ration is low.
You can up the protein in the treats by adding scrambled eggs or some canned mackerel to it.
Distraction is a good thing. Move things in the run around and make sure the one getting picked on has some places she can get to that she is not easily seen by the others. Add new things for them to jump up on and investigate. Even a simple saw horse gives them something new in the run.
If you do a search for hens saddles you will find lots of information on them. There is a thread somewhere on here that has no sew hen saddles. Simple and effective.
I am not sure if blu kote stings when applied to already bleeding areas. Might need to look into that.