Ok, so I was at tractor supply yesterday to get some feed and wanted to buy a wormer for my chickens just as a yearly regimend. The lady that worked there and a poultry farmer said duramycin will kill worms. It's a cleansing agent. Is this true? It doesn't make sense to me at all, it's an antibiotic isn't it? My girls are somewhat on the skinny side and we've ruled out eveything esle, so I wanted to worm to be safe. They also said that is normal for the winter, they get a little rough. IS that true too? My real question is: does duramycin kill worms too? ANy help would be greatly appreciated.