§ 320. Duties of fence viewers as to strays. The fence viewers shall view the premises where damages are claimed to have been done, and they may issue subpoenas, examine witnesses and take any competent evidence of the facts and circumstances necessary to enable them to determine the matter submitted to them, and shall determine any dispute that may arise touching the sufficiency of any division fence around the premises where such damage was done, and from where and how the beasts came upon the lands of the person claiming such damages and charges; if they determine that for any cause the claimants' lien is not enforceable, they shall so certify, and the owner of the beasts shall thereupon be entitled to them without paying any charges thereon.