I would take her back out of the sling, and let her be comfortable. It sounds like she is dying unfortunately. Try to hold a little cup of water up to her beak if she is alert enough. Is she cold? Maybe try a heating pad on low. I really hope that you don't lose her, but I would contact your state vet or poultry lab for a necropsy (autopsy,) if she dies. Refrigerate her body in a plastic bag, and ship or take it on ice if possible. Ask for Mareks testing.
