How many chickens? If you're making say a gallon of Corid water, that needs to be their only water for the next 5-7 days, and a new batch should be made each day. You could use that waterer for it I would assume.
Just looking at the poor thing makes me think coccidiosis.
What's she being fed and are there other chickens or just her? If others, is she the only one acting like this?
She should be laying now so perhaps she's having issues with it. I'd give her one of your calcium +D minimally 300 mg...