Can you post photos?
It could be Cocci, so it won't hurt to treat.
How does her crop feel?
You may want to also investigate other causes/illnesses.
I have provided links to the most common poultry diseases, there is a comparative symptom chart at the end of the first link that you may find helpful.
Also there is a poop chart, to help you determine what is going on.
Common Poultry Diseases:
Corid/Amprol and Cocci info:
Dosage for Cocci is 1 1/2 teaspoons Corid powder per gallon or 2 teaspoons of 9.6% Corid liquid per gallon
Give for 5-7 days - make sure this is the ONLY water available during that time period. Mix a fresh batch at least once a day.