Hiya Shrek! Having read both your recent posts, it could well be tapeworms. What wormer did you last use? A lot of them don't treat tapeworm infestation. Last two posts are spot on - get him treated and get the vet to give him some nutrients and perhaps tested for Johnes (brings back bad memories!! Really hope its not). With this one being a small lamb from the start, he may well not have built up a worm immunity so readily as the others. However, tapeworms have to be really, really bad to kill the sheep and by what I can gather, they are not like liver fluke which can do lasting damage (someone correct me here if I'm wrong!) Good luck and let us know how you get on.