I use a spray bottle. Mix it according to the label directions for use on the chickens, usually 5%. Each product may have a different mix. It may only take about 15 ml, and since most chickens get only one type of lice, I would spray that particular area. The most common louse is the type that affects the areaunder the vent. The next type affects the area around the neck and under wings. You will probably only find them in the vent area or the other two.