A friend of mine who does a lot of homeopathic veterinary medicine said not to use the D-Mannose on chickens, it will kill off their floral balance. All animals have beneficial e coli strains in their gut, killing of the good with the bad can cause OTHER problems... I have been told to use food grade DE in the coop and run, to disinfect the coop, incubator, brooders, and hatching eggs with Oxine regularly, and I'm still using the colloidal silver. Waiting still for a final lab report. She agreed with me that the hens are probably infected with e coli and passing it to the eggs. Good thing we haven't ever eaten any of our Isbar eggs I guess.