I used decapitation on my own and it was a very fast death for my hen.
You want a stump that is as close to "table height" as possible. Hammer in two nails about an inch or so apart. This will help hold their head. Lay the chicken on the stump, gently guiding the neck between the nails. This allows you to stretch out the neck a bit. Hold the hatchet in one hand, use the other hand to stabilize the chicken's body. Choke up a bit on the hatchet and swing very firmly down on the neck. Immediately raise your arm up for another hit if you didn't get all the way through on the first swing. Hesitation is your enemy. I had to kind of pump myself up, and I used the manta "fast and clean" to get in the right mindset. Truly the worst moment of it all was the 2-3 seconds where I had the hatchet raised and I kept thinking "What if I mess this up?!". But as soon as I swung (and then did a second swing to be sure), I felt better. It took maybe 40 seconds total.
Definitely make sure the blade is sharp before using it.
If you're still concerned about using a hatchet, then go with the broomstick method. Whatever you do, though, do it decisively.
