I would treat the whole bunch with Corid. Petrie looks like she has the classic coccidia stance. You do not have to see blood in the poo..as a matter of fact, if you do, it is usually too late to treat as the coccidia has damaged the intestines to the point of bleeding. You can buy corid at most feed stores. You put it in her water for 5 - 7 days. She will start acting happier almost immediately. Do not be tempted to stop treatment early.
Add some yogurt to her diet or some probiotics to help with rebuilding her good intestinal bacteria. Coccidia can prove fatal quickly so start treatment as soon as possible.