I screwed a hook into a convenient overhang, put a thick elastic band around the feet, hang, and slice the head off with a SHARP Chef's knife. Asked about cones very early on, decided they weren't for me and my flock for a host of reasons - mostly impractical due to the range of bird sizes I have and cost ineffectiveness due to infrequency of cullings.
My hook is crude, but honestly, my set up could be duplicated by bolting two blocks of wood to the side of a tree (I'm attached to a 4x4), then screwing the hook into the bottom of one of them. At some point, I'll put something less crude together, but its not a priority.
The important things for me were that it was close to clean running water and a heat source for dipping the bird before defeathering. Oh, and that I could put a bucket underneath to catch much of the blood and bits.