My girls are almost 8 wks old. One of my barred rocks has runny poop. I feed them medicated chick starter but I also let them out of their pen to free graze. I have just noticed that one of them has runny poop. Could this be from letting them out into the yard or could she be sick? She appears really healthy and she is feisty enough but I am worried about her. Could she have gotten into some kind of weed or bugs that might have made her sick? And what can I do about this? Can someone please help me?