No "execution" machine that I'm aware of on the market, and even if there was, I seriously doubt it would be as effective as forcefully slamming the rodent onto a concrete floor. I'm not trying to be funny, or grotesque here either, just bluntly honest.
I've raised tons of rodents when I had the proper facility, but I don't live where I used to anymore, so I find that buying frozen by the bulk, is extremely cheap and convenient, when compared to feeding expense, cleaning, etc...for live rodents, it just isn't worth the hassle and stink for me to raise them anymore.
And yes, after 41 years of owning thousands of snakes, I've had live rodents hurt some nice specimens too, which is yet another good reason for feeding F/T feeders. I'm not about to risk a rodent gnawing on a rare, expensive snake of mine anymore.
Also, the freezing kills any potentially harmful parasites from the prey rodent. So after all is said and done, this is why so many choose to feed frozen.
Large scale rodent companies usually kill their rodents with Co2 gas, it's fairly quick, and harmless to the snake's they are fed to. To be honest, I think "whacking" the rodent HARD on the concrete is a much quicker, and humane way to go, versus being slowly suffocated by the animal. They don't even know what hit them if you do it correctly. If you're going to kill them yourself, I think the "SLAM" method is actually nicer to the rodent, it just "seems" more grotesque to certain humans.
best regards, ~Doug

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"Better to be silent and thought a fool, than to open mouth and remove any doubt!"