At present I use the broomstick method; however, I have always been concerned about the lack of stunning the bird. I am looking at a piece of kit called the Dick Stunner (available online) which is a manual captive bolt. It is very cost effective and when used in conjunction with a killing cone will cause less stress to the bird.
Might be better to search on Dick Captive Bolt Gun, if you search on Dick Stunner you might get a nasty surprise!