Whenever a right of way for a highway is conveyed to a county and the sole consideration for the conveyance is an agreement by the county to construct and maintain a highway on the right of way and to construct highway fences on the right of way boundaries, and thereafter such right of way becomes a county highway, the board of supervisors may, within five years from the date of such conveyance, construct highway fences along the boundaries of such right of way.
Ca. Sts. and High. Code § 967