Available as a dust, wettable powder, and emulsifiable concentrate, permethrin is used on more than 10 percent of the birds (layers, breeders, pullets) treated for ectoparasites. Treatment is most often applied to birds at a rate of 1 gallon of spray ( pound of active ingredient) spray per 100 birds. Premise application at the same concentration is made at a rate of 1 to 2 gallons spray per 1,000 square feet of surface area. Dust formulations ( percent) are applied to birds (dust boxes) and premises (litter) at a rate of 1 pound ( pound of active ingredient) per 100.