Status of flock after wolf attack and validity of non-Jewish testimony

Description

A wolf attacked one sheep in a mixed flock; a non-Jewish shepherd later claimed to identify the specific animal, but the Chasam Sofer rules his testimony is halachically null — both because non-Jewish testimony cannot override a chezkas heter and because boasting disqualifies even mesiach lefi tumo. Since the prohibition was only established upon the Jewish witnesses' arrival, by which point one sheep had already been slaughtered and consumed, the remaining sheep may be eaten two by two per the ta'aruvos rules; as an extra precaution, exchanging sheep with a non-Jew is recommended.