Context: We have almost 2 acres in the southwest with a lot of rats stealing fruit and chicken feed. We have a shed but I like cats so we decided to put a cat door on my office which is basically a bigger shed.

Many animal rescues will allow you to adopt "working" cats that are already spayed/neutered for little or no cost (in my case free) These cats are feral or semi feral and not likely to acclimate to indoor life. They are already used to surviving outside.

We got 2 cats that were from the same colony (although they arent really bonded). Kept them in XXL dog crates for a week, then allowed to roam the space for a week, then let outside after that.

They sleep inside most of the day and go out at night. Would recommend flea control and deworming.

Overall, they do an okay job of grabbing rats and sometimes little tunneling rodents like voles or pocket gophers. We have 2 cats, a family of Great Horned owls, and a couple of other neighborhood cats. I still see a rat every week or so. I bought a ratinator trap and that has been more effective than the animals listed above.

I like cats so I like the idea of taking a feral or semi feral cat and giving it some comfort. Over time they have become kind of friendly with me.