Is it hot where you live? How long has she been like this? She could be weak from dehydration. Get some water and add electrolytes and vitamins, such as SaveAChick, and give it to her by dipping her beak or giving it with a dropper. How old is she? Can you check inside her vent with one finger an inch or so, for a stuck egg? If you can get her to drink some, then offer some chopped up egg or some tuna. Have you seen any of her droppings? Coccidiosis could make her weak. Symptoms are lethargy, hunched posture or extreme weakness, not eating, and runny droppings with mucus or blood. Corid is good for treatment. I hope you can get her drinking soon, and Pedialyte or Gatorade will work temporarily.