I am also interested in this as my snakes are requiring larger feeders......and I really hate dealing with frozen / thawing, hearing the animal scream at kill ( and i would imagine a rabbit can let out a pretty nasty screech)and just cant handle thwacking them on the head or see myself swinging a pillowcase.....tried it and all i could manage was giving the jumbo rat a headache.......
anyway i have been reading these articles and will be constructing my own kill box as the Euthanex system is very expensive....around 450.00. Maybe these will help:
http://labanimals.stanford.edu/Guidelines/CO2.html
http://www.euthanex.com/euthanex/index.htm
