The one that sold on the 2017 spring "wrenchingnews" auction included documentation on it's role as an expeditious chicken killer (instead of slashing the neck arteries, just crush the brain stem ) --
"0530. Unmarked - - 8" cast aluminum pliers like tool. Identified by markings on one found in the original box as a Humane Chicken Killer made by W. J. Fisher &: Son's of St. James, Man. Canada and Independence, Missouri. Patented was granted May 25, 1937 to William John Fisher and I assume his sons: William Alred Fisher, Alvin Clarence Fisher, Evans Fisher and Victor Hubert Fisher all of Tyvan, Saskatchewan, Canada. According to the patent the pliers is used to pierce the brain of the soon to be Chicken McNuggets thus causing instant death. Excellent, like new. "