As used in NRS 569.431 to 569.471, inclusive, ‘legal fence’ means a fence with not less than four horizontal barriers, consisting of wires, boards, poles or other fence material in common use in the neighborhood, with posts set not more than 20 feet apart. The lower barrier must be not more than 12 inches from the ground and the space between any two barriers must be not more than 12 inches and the height of top barrier must be at least 48 inches above the ground. Every post must be so set as to withstand a horizontal strain of 250 pounds at a point 4 feet from the ground, and each barrier must be capable of withstanding a horizontal strain of 250 pounds at any point midway between the posts.