I. Miscellaneous background info: At night I can see half a dozen rats crawling around our run in the beam of my flashlight. Between my dog and me we've scared a fair few but they persist. I have tried: snap traps, electronic trap, cat, and various products from predatorpee.com. These rats are smart, suspicious/cautious, determined, and very numerous! With 7 beautiful tomato plants in the garden we got zero tomatoes this year- all eaten before ripening. We have a "chicken moat" around our garden and I have dug into several rat holes so I know they are living all over the place. I also found a nest of babies in my compost pile a few months ago. Uck. II. My objective: to have an ongoing rat control method since it's likely to be a chronic problem out here. Rural, with near neighbors reporting they get rats too. I am not interested in any method that is only practical for a minor rat presence. I also really want to avoid cruelty!! III. The alternatives we are now considering: 1. Bottle/bucket method. They go after the peanut butter on the bottle held sideways on a wire over a bucket of water, fall in ,and drown. How fast is this? Do they try to tread water for hours? minutes? until, exhausted, they succumb. How humane on a scale of 1 (torture) to 5 (quick death). 2. CO2 method. Catch rats by luring into a bucket with a lid, small hole in the lid and bait inside -- they drop in to eat and cannot get out. You attach CO2 tank (such as used for paint ball) and slowly gas them. (Alternatives: baking soda vinegar method or dry ice method.) Questions: I understand the CO2 level is critical for painless death. How hard is it to achieve the right level? Refilling the small paint ball tank costs $4.50 -- how long would that much CO2 last if I am exterminating every day for a week and then maybe once a week thereafter. Has anyone used this method in a farm situation? Cost effective? Has anyone here tried this? 3. Plaster of paris mixed with food. How much do they suffer while the contents of their bellies harden? I know they are pests and I hate having them here, but I cannot help wanting to be humane. 4. Shooting with air rifle or air pistol. We're not spending the night in the chicken yard, so how hard would it be to use a weapon on trapped rats, such as in the first step of the CO2 method? Is it hard to hit them? Do they generally die right away? I know some here will be annoyed by my concerns about humane treatment and what will be viewed as "wimpy." I apologize for taking your time. I just want to hear practical suggestions and opinions please. Thank you very much for reading my questions!