I personally prefer CO2 - done correctly using a regulated canister it causes anaesthesia then humane death.
I do not have faith in my ability to break necks or 'big swing' correctly the first time I try and every subsequent time after that, so I do not feel I have any business doing it knowing I could cause additional pain, stress and fear to the feeder animal.
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- Ssthisto
"My bum has been a bum for a very long time, but that doesn't mean I have to listen to what it says."
- Terry Pratchett, Fifth Elephant