ok garden loppers. do you have a picture? I am preparing to process and really don't want the ax and a stump option that the DF wants to use. So I am going to get a cone and something to cut their heads off.
I would not recommend cutting heads off to kill. As soon as you would lop the head off, body and neck are going to be twitching all over the place, blood is going to be spraying and it will be a mess. Because you can't hold onto the head and lop, need two hands to use loppers. This is what I do:
Put bird upside down in cone.
DP holds feet, but if he is not available, I tie the feet together using something quick and easy, like heavy long twist tie
Position 5-gal bucket with a couple of inches of water in it, below where the blood will drain. I also put a large piece of plastic down to catch any blood sprays, but I'm doing this in my garage, not outside. Don't want flies bothering me! The water in bucket will help with clean up.
Use VERY sharp knife. Key is the knife needs to be VERY SHARP! Grasp head, tilt it to the side for correct angle to access jugular, one quick slice through jugular, right under the head. No sawing motion. Blood should immediately gush out if cut was good. Don't cut too deep, you don't want to cut the esophagus and get material coming up from the crop which is yucky. Did I mention you need a good, sharp knife?

Continue to hold head while blood drains and until bird stops twitching, otherwise you will have blood everywhere. Wear old clothes and old shoes that you don't mind being blood stained because accidents happen!
Plan ahead and withhold feed and water the day or at least the night before you butcher. You want the crop and intestines empty so you don't contaminate the meat when gutting them. Also plan ahead and have ice ready. We freeze 1 gal jugs of water and put those in a bigger container of water for chilling the birds after plucking so we don't have to buy ice.