What symptoms is she exhibiting now. Is she lethargic, puffed up, wobbly, etc.
What type of food/treats does she get?
Does she now have access to grit?
It does almost sound like Cocci. Corid is very gentle and it won't hurt to treat for Cocci.
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.
Afterward, give some poultry vitamins in the water for a few days, and a bit of plain yogurt for probiotics. Here are 2 good articles to read: