Please allow me reiterate what "rainbows-r-us" said;
A CO2 chamber.
If you've got a couple of boas that you need to pre-kill prey for, do you really want to be whackin' rabbits in the back of the head 20 years from now?
I made one a few years ago and I went overboard and even bought from an expensive place. I've got about $100 in mine but they can be made for less. I was thrilled & proud that I made one the first time I put some rats down. And I ain't no PETA fan, either. They simply go to sleep and a minute later they're dead.
I can put down about 30 large rats or 2 - 6lb rabbits at one time. For mere pennies more, you can make it even bigger. The main costs are the tank & valve. The hose, gas and tub are cheap, unless you go with a braided hose like I did. the plastic, coiled air compressor type hose is cheap & just as effective.
Spend the money, you'll be glad you did.
Have a good one!
Mike
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It is said that 1 out of every 4 people are mentally unbalanced. Think of your 3 closest friends, if they're normal, then it's you.