[Redbob]

"Then the rats came. They invaded my farm last summer, especially the big barns."

There are other more one-on-one solutions than cats...

[Inge_CAV]

There are many more mice and rats on a farm than you can hunt down and shoot. If you have driven a tractor to mow a hay field you will have an idea of just how many there are, lots. Cats are welcome, also snakes, hawks and coyotes. Even chickens will kill and eat mice.