Living in the country with a lot of bush and fields around can lead to severe mouse trouble because there’s effectively an infinite supply of them, so whatever population your living area supports will always be packed full up to that limit – the “carrying capacity” of your house! Killing them or trapping and transporting them is just a waste of time and energy because removing them simply creates a vacuum which will be quickly filled by the surrounding population. So the only answer is to reduce the mouse carrying capacity of your environment, and to make sure your house is well sealed against them.
Sealing against them means that every tiny whole in the foundations or roof such as under corrugations must be filled. Ideally with concrete or wood, but for the more difficult areas steel wool is a good option. Also putting peppermint oil around can help to make the area distasteful for them as the smell is too strong for the little critters.
Reducing the carrying capacity means ensuring the immediate area surrounding your house has no places they can make nests, and making sure that you’re not offering them food by keeping your compost sealed against them. As well as making sure that any space in the foundations, ceiling and wall are sealed, it’s important to ensure that the area around the house is tidy, because mice love to make nests under piles of wood or other rubbish.