I have had chickens for 5 years and never had any serious problems, until today. When I let the chickens out of the coop, one didn’t come out. She was laying on the ground trying to get up but couldn’t. Her legs wouldn’t work and when she tried, she would stumble. I have her isolated inside. I gave her nutri drench and shortly after she was able to stand and walk, although not as quickly as a normal chicken. I gave her vitamin/electrolyte water, although she’s really not drinking or eating. She has diarrhea but it’s not bloody or abnormal looking. She is a little puffed up but really only when I try to touch her. Looking at symptoms of coccidiosis, they sound similar to what my girl has, except for the legs and not being able to walk (now she is fine walking but stays laying down). All of the other chickens are fine. What could this be? Is it simply a vitamin deficiency or something worse? And now should I treat it?