Treating botulism I think..?
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I would not try the Epsom salts flush, since that may cause diarrhea and further dehydrate her. Botulism usually progresses quickly up the spinal cord causing total paralysis within a day, so I doubt that she has botulism. There are other diseases that she could possibly have, including coccidiosis, aflatoxin poisoning from decayed or moldy food, or Mareks. I really hope that she can survive this with your good care, but if she passes away, I would get a necropsy done on her refrigerated body by your state vet or poultry lab. Right now I would give her chicken vitamins, such as Poultry Cell vitamins 1 ml per every 3 pounds of weight daily, given by mouth. Since she has a respiratory illness, that can also point to an immunity problem, since Mareks disease can cause common illnesses such as cocci and respiratory diseases to be more of a problem. Beow is a link about botulism, and here are some links about Mareks disease and aflatoxin poisoning:
Clinical Findings of Botulism, from The Merck Manual
Clinical signs in poultry and wild birds are similar. Leg weakness and paresis that progress to flaccid paralysis of the legs, wings, neck, and eyelids are characteristic clinical signs. “Limberneck,” the common name for botulism in birds, comes from the neck paralysis typically seen in affected birds. Signs in broiler chickens may also include ruffled or quivering feathers, feathers that are easily pulled out, labored breathing, and sometimes diarrhea with excess urates in loose droppings. Severely affected birds are in ventral recumbency on the floor with their eyes partially or completely closed and neck outstretched. They are unable to lift or hold their neck up and cannot raise their eyelids because of the flaccid paralysis that develops. Affected birds may have their legs extended behind them, because they are unable to pull them into a normal sitting position. Weakness is the earliest sign in waterfowl. Birds are initially reluctant to fly when approached and have weak wing-beats and difficulty taking flight. As the disease progresses, they lose their ability to fly and exhibit stumbling gaits and eventually paralysis. Birds in water can drown, because they cannot keep their heads above the water. The incubation period and time to onset of clinical signs is determined by the amount of toxin absorbed.