My vet in the UK told me to put Frontline on the chickens. Year later, I was importing commercial incubators from China to the UK, so I met a lot of fancy poultry people, and I heard the same thing from them -- they put Frontline on their shiw birds. For those unfamiliar with it, Frontline is dripped onto the neck of dogs to control fleas and ticks. I wouldn't eat the eggs afterwords but it certainly works, and you xan't eat the eggs for a few months no matter what you put on them, so why not just use Frontline?