help chicken very blooming

hi everyone. need help quickly please, just noticed one of my hens has blood all around her bottom, her feathers are missing too and the two other hens wont leave her alone, so i have split them up but dont know what to do next. As far as i can see it looks like they have done this to her but now my hubbie is home we are going to investigate more 

thankyou very much for your reply, i did gently wash her and there was no sign of a prolapse, the other two had done the damage i think, she now has a purple bottom and not long after that they went to bed, but i'm worried it will all start up again tomorrow in which case dont know what we can do. I have been told that now she has purple bottom they should leave her alone as it isn't red anymore. Hope so!

if she starts bleeding again then sprinkle wound powder on her (if you don't have any to hand then cornflour will do in an emergency but wound powder is medicated). She may have laid a shell-less egg and if it broke on the way out the other hens would have started to peck at it then got carried away.

hi, she is hiding herself away in the nest box today although she has been out for aome food. i now wonder if she is egg bound and if so what can i do?