When you treat chickens for external parasites using sevin dust; not only do you have to dust your chickens, you have to dust inside their coop. That includes nests and roosts. Then you have to redust your birds and inside the coop again in 7-10 days prior to the parasites reproducing.
An easy way to dust inside the coop is to put a handful of the dust at the entrance to their house. Make sure all vents are closed or covered and no chickens inside. Next, get your leaf blower and hit the pile of dust full blast. It'll look like a smoke bomb went off inside the coop. I guarantee you the dust will get in every crack and crevice and take care of the parasites and any other 6 or 8 legged bug. It'll take about 30-40 minutes for the dust to settle, then open the vents. Use a broom to 'pat down' the bedding on the coop floor and nests. Where old chicken clothes/shoes and mask when you do this.
As for the chickens themselves; put a good amount of sevin dust in a paper grocery bag. Then grab a hen and put her in the bag with her head sticking out the top. Grab the bag where the neck is and hold on to it. Then "shake and bake,"...gently rolling her body around inside the bag ensures she gets covered with the dust. Then let her out of the bag, she will shake herself off and go about her business. Then grab the next bird and repeat until all of them have been dusted. If lice are on the head, after the shake and bake, simply use your fingers to gently rub the dust onto her head and neck areas..avoid the eyes and nostrils. Then release her and go to the next bird. Again, wear chicken clothes/shoes, mask.
