live rat problem

[The Serpent Merchant]

Why even make a CO2 chamber? You can just bonk the rat or dislocate its vertabrae near the neck. Quick and painless death, and you save the money.

Bonking them isn't considered a humane way to kill rodents... I've done it but I certainly wouldn't consider it to be quick or painless. CO2 chambers are really good if you need to kill a large number of rodents at a time.

To the OP here is another version that works pretty well: http://www.rodentracks.com/DIY_Co2_Chamber.html