I use Tomcat bait chunks in the trailer shed and tractor barn. Put them up high enough a dog can't reach. One of my trucks is always in the tractor barn out of the sun.
I had a issue with a pack rat family some years back. I left a radio plugged in 24/7 to a head beater station. No more issues any pests.
I use a mouse trap just inside the 5th wheel trailers door baited with peanut butter. I'm always around the barns so I check it every couple of days.
Both barns have a hay meadow along the back side. Both are open one side so owls also do a good job on rats/mice.