3 Pa. Stat. § 326
Any magistrate, alderman, or justice of the peace, upon the trial of any person charged with the violation of any act for the prevention of cruelty to animals, shall inquire into the condition of the animal or animals charged with being ill-treated or otherwise abused; and if it is proven to his satisfaction that said animal or animals are so injured, disabled, or diseased past recovery, or unfit for any useful purpose, he shall direct as part of the sentence that such animal or animals shall be humanely destroyed, and shall authorize any policeman or constable of any borough, township, or city, or any agent of any duly incorporated society or association for the prevention of cruelty to animals, to carry that part of the sentence into effect.
3 P.S. § 326