Once I had a chick who was hit hard by cocci. He never developed as well as the other males in his age group. He was the only one hunched up and showing weakness, which is what alerted me to treat the group in the first place. I thought I'd lose him, but I didn't. He eventually recovered, but never grew to his full potential. Plain active culture yogurt is a good probiotic, but there are other packaged ones you can find at the feed store for this purpose. There are show bird conditioners with vitamins, minerals, amino acids and probiotics together you could give the entire group, but they'd do her the most good, I bet.