Missouri Revised Statutes Title XVII. Agriculture and Animals § 272.210. Definitions

(1)“Lawful fence”, a fence with not less than four boards per four feet of height; said boards to be spaced no farther apart than twice the width of the boards used fastened in or to substantial posts not more than twelve feet apart with one stay, or a fence of four barbed wires supported by posts not more than fifteen feet apart with one stay or twelve feet apart with no stays, or any fence which is at least equivalent to the types of fences described herein;

(2)“Stay”, a vertical member attached to each board or wire comprising the horizontal members of the fence.