Rear a Truncata or some other big pitcher Nepenthes, so that the plants will have revenge!
I am wondering if they are cutting it because they can't get into the pitcher, so cut it, and bring the pitcher to a hiding place and eat what is inside. So maybe a bigger pitcher will make them go in and get caught.
We don't really use rat poison often, what we use are those mouse traps that look like cages, these traps the mice or rats and you can either let them go or drown them.
Next time if you plan on buying a dog, get a small terrier one like a Jack Russel Terrier, but then they are so hyper active that they are a handful sometimes, they might also tinker around with your CPs too. Now I wonder if those utrasonic or whatever anti pest device will actually work, maybe you should try those? They are electronic devices that you plug in and they are said to emit a noise that rats don't like.
TTFN
Arvin