Any Tips On Muscovy Duck Slaughter?

Has any of my readers done this? I've killed just 7 roosters so far (decapitation via machete) but now my Muscovy Duck flock needs thinning, and I want to try the meat. But I want its demise to be quick...any tips? I've considered my machete, my pellet rifle, my aluminum baseball bat......videos of throat slitting make it look like death takes a LONG time. Soul of a vegetarian here but body chemistry of an omnivore trying to wean myself from factory farm meat. Thanks in advance for any suggestions for a humane slaughter. John