I've noticed that Nellie has been lethargic lately. I thought it was because I put too much DE in her dust dish and she probably inhaled it. I washed her and her cage, and took it out immediately. Now I see that she can't stand, and flops down as soon as I let her be. She uses her wings to try and balance herself and barely move on her own. She's very sleep all the time. There seems to be sores behind each of her legs, behind her knees or hocks or whatever it's called. Yesterday I really thought she was going to die. I know nothing about chickens and I really don't want to be the cause of her death. Is this something treatable? What should I do for her??