There was a big tom that kept taking my young chickens when I was a kid. He would hide under the asperagas then grab a pullet when one got close. He would drag it into the long grass and kill it.
I saw him under there one day and I shot him right in the face with my pellet rifle. He jumped up like he had been electrocuted and flopped back down and never moved again.
A .177 pellet to the head will do the trick.
-Brian