We are new to raising chickens and have found we have a problem....our 5 month old blue cochin doesn't look or act sick but when we pick him up is extremly thin...can feel his breast bones and no meat on him (sorry I don't know all of the correct terms). He has also had runny green poo for a couple of weeks now. I am suspecting worms. Does this sound possible? How do I know if I need to treat for worms? What things can we feed him to get him healthy again? So far we have only been feeding the starter crumbles. Do we need to seperate him from the rest (2 buff cochins & 3 polish crested)? If it is worms do we need to treat the whole flock? Thanks for any help!