Some mice and Norway rats are resistant to warfarin. Which is what most of the poisons you buy at your local Home Depot type store sells. That's also why I mentioned a commercial poison by name.
As to morbid, well I could shoot them with the .30-06 but it makes too big of holes in the walls and I don't have time to sit and wait for a mouse or rat to poke his head out between chewing on my car......
And small mice won't set off spring type traps untill you fatten them up with that treated seed.
Mice chew on everything and what they don't chew on, they pee and poop on the rest of it. If you have ever had a mouse problem you wouldn't care what got rid of them.