Our sussex 9.5 weeks old, who was fine yesterday, wouldn't come out of the coop this morning. She could move her legs and looked like she was trying to get up but then she would kinda fall forward... (like doing a downward dog in yoga). We are really worried. Her feathers are ruffled and while she seems perky she isn't as perky as usual. Her droppings are runny, stinky to normal. We thought there may have been blood in it but may have just been that intestinal lining the pass occasionally. No obvious fresh red blood. We brought her in the house and isolated her and she is eating and drinking quite well. We thought she had cocci a few weeks ago- she had blood in her droppings and we treated the whole flock with Corrid and an antibiotic added to the feed since they were in the brooder together and she improved with treatment. Now, i'm wondering if it wasn't cocci but worms instead? or is it Marek's? would worms do this? would i be able to see them in her droppings? We are new chicken owners and just don't have a lot of hands on experience with illnesses... and i don't know what our next step should be? What can we do to protect the rest of our flock from this??? What does Mareks act like- are all of our chickens about to drop dead?