Will do Dogwalker thank you. Also just spotted a March posting on the sheep section on the subject with good input from Shep53 & Me too. My lambs aren't showing all the classic symptoms of listeria, that's for sure. I did suggest bacterial meningitis to the vet as a possible but she didn't seize on this. Given the mole activity in their new field and the lambs' fascination for the damn molehills, early stages of listeriosis seemed to be best guess given no other firm diagnosis. My long-suffering husband has just been back to the field and fenced them back in their original area to keep them away from the molehills - this may well have been a fool's errand but we've just got to try everything. Thanks again everybody. We are going slowly nuts with this.....