What are Mr. Parham's instructions for Billy when he heads out to check the wolf traps?

Billy goes off alone the following day to run the traps with his father's instruction regarding what to do if he had caught the wolf. He's told to come get his father unless the wolf's leg is broken, in which case Billy is to shoot her because she might otherwise "twist out." Billy has no more luck than he and his father had had with the previous sets but does find another dead cow, this one a two-year-old heifer.