Wyo. Stat. § 11-28-105
The board of county commissioners may authorize the erection of a lawful fence upon the right-of-way of any public road at the expense of the petitioners for the establishment of the roads, or as may be agreed upon between petitioners and the board of county commissioners, or at the expense of the owners of lands to be benefited by the fencing or at the expense of the county, as the board of county commissioners may determine. The board shall locate and cause to be constructed gates and cattle guards at such intervals as it deems necessary for the convenience of the public. Cattle guards shall be constructed according to specification prescribed by the state highway department, under the supervision of the county surveyor or county commissioners at the expense of the petitioners, the land owners who may be benefited, or the county as the board of county commissioners may determine.
W.S. 11-28-105