I'm guessing you don't have a cone to contain the flapping. A milk jug can be used if you expand the hole a touch so the head can get through it. but you still have to nail the jug up somewhere you can get a bucket underneath to catch stuff.
there is the AX method but many say it takes a heavy swing and you have to keep the chicken's neck in the right place.
for us we went out and got a super sharp knife and we cut the 2 main veins. it is messy but the flapping is contained as we have a cone. For me now the removal of the insides is the hardest part.
What about sleeping pills dissolved in a very little bit of water, you could get her to swallow it using a dropper.
i read the link you posted, even though it came right out and said all that it makes me feel better to hear all the truth. mo i font have a killing cone. i am seriuosly thinking about hanging her up by the legs sayingmy last good byes cutting her throat,. and running away without looking back. i feeling i would look back. i never really thought sbout drugging her. Which ever way i go i know i am going to feel bad. i might as well puck a way and get it over with. If it makes any difference i am not going to eat her.