I am new to this forum and recently returned to backyard chickens after many years of city living. My problem is a sudden influx of flies in the chicken pen. I seem to remember that there is some kind of lime that can be sprinkled on the dirt in the pen for fly control, but don't know which kind or how much to use without hurting my girls. I have 6 Barred Rocks that are just starting to lay. They are hand raised pets, so I don't want to hurt them. Thanks to anybody who can shed some light on this.