In my opinion, the hatchet is the most humane because it's the quickest death for the chicken. That being said, if I were doing it on my own, I'd probably use the cone, but still decapitate. I just don't think I'm coordinated enough to try the hatchet and stump.
Depending on the chickens, we'll either scald (dip into the hot water) and pick them, or skin them. I gut them all. The old hens get skun out, kept whole, and either frozen or refrigerated to be canned. (I have an electric pressure cooker now, so I am probably more likely to just freeze them and cook them one at a time. Once I have used most of the meat - legs, breast, wings - I put the carcass back in my pressure cooker, add veggies and spices, and cook for another 1 1/2 hours to make bone broth. Once you've tried that, you'll never want to buy broth again. If you don't have a pressure cooker, you can cook them and make the broth in a crock pot. It just takes longer.
We scald and pluck the ones we plan to use for roasting or grilling.