I can't imagine a house mouse would survive very long in open countryside. But as you say (or do you?), being torn to pieces by a bird of prey is a much more humane way of dealing with them than is instant death in a mousetrap.We have caught eight of them in our larder the past couple of weeks. We use peanut butter and a humane mouse trap which means they have to wait a few hours until we get up, drive them a mile away to open countryside, and release them.
Seems a shame to kill them when they could live to fight another day, well away from our house. Or at least provide a tasty meal for an owl or other predator.
We did use chocolate as bait for a while but peanut butter seems much more effective.