I have used it for feather mite. The ones which eat the chest feathers. Just smear some on with a cotton bud then repeat about 2 weeks later. It's difficult to tell if it has worked as the feathers need to be moulted. Cots to me from Chemists direct was about £5.00 for 250mls. Enough to treat the entire federation. At one time it was the recommended treatment for seaside nippers in humans.