Hi. I have a 10 week old black sexlink. She's top of the pecking order of our 5 hens. She's mostly active, doesn't act sick, and then closes her eyes a lot and just rests. Had her tested for parasites and cocci which came back negative. She did have some bloody poop for a few days but doesn't now. Mixed medicated crumbles into the feed. Tried molasses flush and ACV in the water too. The others are all acting fine , and she acts normal, but then closes eyes and droops. I've also checked her for mites... None. What could this be?? I've only had them a few weeks. Came a reputable farm. Should I treat with Corid in the water just to be safe? If they don't have cocci does it hurt them to take it?