The only reason I included this last piece of info is because of your mention of the red face and the pics of the blueish discoloration. It could also explain the nerve involvement of the legs. If by some odd chance this is what is wrong, it goes back as well to the septic call Casportpony made before. Please find and contact your state Vet. and extension service. They are going to be a big help to you now and later on, if you continue with keeping chickens. I don't mean to be harsh, but having learned the hard way, there are some things we just can't do ourselves and we need professional help. The only other alternative we have is culling. I have no clue what your bird has or if this is a genetic issue. Either one could be true. You need to know where this bird came from and research to find if this is from the original flock or a fluke.