Many breeders consider pens better and cheaper than dens. These are little runs about ten feet square, separated only by a three foot netting which has an inhang or overhang as it is some times called, of a foot on each side, so the skunks cannot climb in or out. If boards are used for pens inside the big fence no overhang is needed. All pens should be completely floored with mesh wire three or four inches under surface.