Great thread. Just sorry I really need the info. Dang it!! We have a rat problem. They have dug under the slab foundation of the barn. When I say dug I mean they have made a huge condo under there. Now I know why the cement floor is cracking. After further inspection we have found that the barn has sunk about a 1/2 inch on the west side. There was nothing left to hold up the building. The sill plate is about 6" off the ground. So we have dug new footings for support under the sill plate. Yesterday was doing some remodeling moved a bunch of stuff saw a couple big holes thought no problem just fill with cement. While digging to set some forms. 2/3 of the foundation gave way! There was a huge housing tunnel and dens the rats made. I had hubby come home with a friend so we could get things taken care of. Hated to do that but 2 of the 4 sides of the barn no support. I don't even want to know about the west side. At least the north side is fine.
During this process our boston terrier Goblin has turned into a very good rat hunter. Getting better with all the experience he is getting. He has only been able to catch and kill young ones about 40 so far. 40 little rats. Crap almighty this must mean we have tons of rats.

Goblin has even found them in the green house and now he is alerting on the back porch. Crap!!!
Needless to say once all the new foundations are in and holes plugged we are going rat hunting every day!
So according to this thread I will try
A trash can with bait string and a board to try and catch them
Rat traps
shooting them
gassing them
wack with a shovel (got only one that way the second got away)
poison if we can get the summer home made for our pigs and birds. (pigs love baby rats know I know why they were digging in the barn)
Borax and peanut butter
Cats ferrets snakes ( we live in SW WA) more dogs water hose under slab options not really doable.
Did I miss any thing? besides call an exterminator? We keep all feed in metal garbage cans. Have never had a rat chew through the bags of extra feed (never really saw that much poo either). Will also try and make some kind of nipple watering system so we don't have to have buckets of water around. That won't work for all the animals so will still have to have some open water source.
THIS IS WAR!!!