Lime green poop, in my experiences, has always had to do with wasting. You never know they're wasting till they reach the end of the line and you get green poop. I'm Not saying that this is true 100% of the time, but it is for me. I'm neurotic about checking under the roosts every morning. Most, if not all of my lime green poopers were at the end of the wasting from Marek's disease. Others have different experiences, like SpeckledHen. Lime green poop will happen to any chicken that has stopped eating for a period of time. From a number of illnesses.