Ive killed more chickens than I could count..The best type of axe Ive used for be-heading is one with a flat blade profile, like a carpenters axe. Just like square peg posted...Theres less room for error..Pretty much gonna get a good clean kill everytime..Ive done it with hawks too but you gonna be dead-nuts on everytime or it will take more than one lick..I like the head to come completely away first time..
Though to be honest I havent been cutting off heads in a long time..I just grab and go..Wring its neck and toss it down, go to the next one..I can kill out a house in minutes that way..
Non timebo mala, quoniam tu mecum es
Behold, I have created the smith who blows the fire of coals and produces a weapon for its purpose..Isaiah 54:16