The governing body of any county is hereby empowered to adopt ordinances making it unlawful for any person to carry or have in his possession, for the purpose of hunting, while on any part of a public highway within such county a loaded firearm when such person is not authorized to hunt on the private property on both sides of the highway along which he is standing or walking; and to provide a penalty for violation of such ordinance not to exceed a fine of $100. The provisions of this section shall not apply to persons carrying loaded firearms in moving vehicles or for purposes other than hunting, or to persons acting at the time in defense of persons or property.