Decapitation
Benefits: fast Drawbacks: holding the bird and using an axe or hatchet; making it a clean cut; large volumes of blood spraying out.
For many the historic and only way considered to kill a chook is by chopping its head off. This is a quick method as long as the head is severed completely at the first blow; the bird is immediately unconscious and bodily functions cease.
There are a couple of negatives. One is holding the bird in the right position (you can wrap it tightly in a towel or blanket) and wielding the axe/hatchet with the other. There’s the risk of doing yourself an injury, or injuring someone else if they are holding the bird for you.
Decapitating a bird also releases a large amount of blood very quickly, which tends to go everywhere as the bird will still move due to nerve spasms. Also, if you are killing a bird for meat and need to dunk it straight away into hot water (to loosen feathers to help with plucking), it can get very messy.