I use a very sharp meat cleaver style of knife to chop the head off. I then hang the bird upside down for about half an hour before giving it to DW for processing. She uses any smallish knife for everything.
Sometimes when I slaughter, I hang the bird outside in an area where it won't be in the sun for about a day and a half prior to plucking. When I pluck, I scald for about two full minutes as I've found this works best with the Thai game birds. If I just can't be bothered plucking, I simply skin the bird instead, but I don't like don't that really because we often use them for soup, and the skin adds a lot of additional flavor.
I know some on here will frown at me hanging the birds for so long without refrigeration, but these are game birds I'm dealing with, and believe me, I've tried several different approaches. You can hang a chicken for a few days and it will still be safe to eat, just as you hang most types of meat, and especially game.
Talking of which, here in Thailand, Thai beef is incredibly tough, or at least I thought it was until someone explained why. The reason being, is because when a cow gets slaughtered, it's cut up and on sale at the markets within minutes. The Thais don't seem to have caught onto this whole "aging" thing. Now when I buy beef here, I let it sit in the fridge for days on end, or if I'm in a hurry for it, I tenderize it with unripe papaya. If I'm cooking it only for myself, toughness is not an issue because it barely get's time to warm up
Nothing like a huge steak which is only lightly cooked over some hot coals. The rest of the family prefer it well done, so most times I'm out-voted
BTW, just use whatever knives work best for you