Recovery, Possession and Sale of Bighorn Sheep Horns: Horns from bighorn sheep that have died of natural causes may be recovered and possessed. All bighorn sheep horns must be presented to Fish and Game for marking with a permanent pin within 30 days of recovery. It is unlawful to sell, barter or purchase bighorn sheep horns obtained under these circumstances, or to transfer ownership of recovered bighorn sheep horns without a permit from Idaho Fish and Game.