When the owner of any inclosure wherein foxes or other fur-bearing animals are held in captivity, shall erect a fence or other barrier around the same and within the boundaries of the premises under the exclusive dominion and control of such owner, and shall post warning signs in conspicuous places along such fence or barrier prohibiting trespass on the clear space between such fence or barrier and the inclosure aforesaid, it shall be unlawful for any person, without the permission of such owner, to cross such fence or barrier or trespass upon such clear space.