Chickens dehydrate so quickly so the first thing I was told to do is give electrolytes with a syringe here is a recipe
- 1 cup warm water
 
- 2 teaspoons molasses OR 2 teaspoons granulated sugar
 
- 1/8 teaspoon salt
 
- 1/8 teaspoon baking soda
 
- 1/8 teaspoon potassium chloride* (optional)  potassium chloride is salt substitute.
 
If you don’t have it all salt and sugar . Quickly. I hope you figure  out what is wrong.  It could be starve out, your solution is electrolytes and raw eggs yolk with a syringe.
 
Edit sorry I forgot
If you don’t have syringe soak up a bit on a towel or napkin, use your finger to part her beak and squeeze a drop on the edge of its beak. She might drink it herself, try dropping some on the top of her beak she might open but I doubt it you are going to have to force feed.
good luck