I have been reading threads on gape worm. Many say the only treatment for gape worm is ivermectin. DE is effective in preventing worms... De kills parasites internally when the chicken injests it. Razor sharp, damages worms, dehydrates worms, etc. My first question is.... how can DE kill parasites inside the chicken body where it is wet? I use DE in the garden to kill slugs and snails. It works the same way but when it becomes wet it is much less effective. My second question is... if it really does kill parasites, why would it not be effective against killing an already established parasite colony? With multiple treatments? I have one pet chicken that is showing signs of gape.... I am thinking about treating her with ivermectin. She doesn't lay eggs. But I don't want to treat my layers with this drug. I sell my eggs and I can not, with good conscience, just decide to discard for a certain number of days after treatment and then sell more eggs. The people that buy my eggs are looking for a better, safer product than the eggs found in the store. Treating with a drug that is not even approved for chickens seems risky. There are lots of posts saying how long it takes before the drug leaves the body and eggs, but until scientists have tested it, we don't really know.