Wash. Rev. Code § 16.57.245
The director or any peace officer may stop vehicles carrying cattle or horses to determine if the livestock being transported are accompanied by a certificate of permit, inspection certificate, self-inspection certificate meeting the requirements of RCW 16.57.010, or other satisfactory proof of ownership, as determined by the director.
[ 2010 c 66 s 10; 2003 c 326 s 29.]