[Thanks for starting this thread.
I too am in a long standing war with rats....and I too "hate" rats for the filth and disease and parasites they bring into the property.
I find a multi-method approach the best.
In our area, you can only get ahead for a bit. Rats proliferate everywhere. Often it is a matter of harassing them enough so they go to the neighbors until they harass them enough to send them back to you.
What works for me?
1. Cleaned up as much feed as possible and cover or removed over night. I have reinforced coop entry ways only to have the monsters chew THROUGH the wood in the coop. I have stopped feeding in the coop altogether. (There was reason I had feed in the coop at one time, for broody mommas and babies, but if you can avoid it do.)
2. Made it hard for them to get to stored feed. My feed is kept in a metal garbage can with lid. They chewed through any rubber maid, even the super tough kind.
3. I have tried the plaster of paris mix. It does work, for a little while. Mix it wet, add bird seed or such, and form little wet but firm balls to place in areas chickens can't get to. Replace in a couple of days. The first couple of rounds, it did stem the tide...then no longer worked.
4. I have found a good cover for my tin feeders to be a 5 gallon bucket placed over the top. It sets down into the bottom metal lip so that the rats can't seem to get a grip enough to gnaw through it. I get very little waste out of that feeder type overnight. My birds don't seem to spill a lot of feed when I have the feeder placed up high enough so they can't bill it out well.
5. I've added natural control. We've had hawks and owls help out (although they tend to help themselves to the birds as well...so I've got a lot of hawk netting to.)
Last year, I got a Rat Terrier from a rescue. Just this summer he has 13 rat kills. I've trained him to not bother the chickens, even the smaller grow outs (still wouldn't leave him alone with baby chicks). He is faithful and diligent in his nightly rounds. I let him hunt rats as I check and lock up birds at night. We also send him out for a bit on his own (for about 20 to 30 minutes). I monitor him as I don't want him eating the rats (for the pests and potential poisons). He is really good about bringing the kills to me. (He prefers jalepeno jack cheese to rats
6. We've set up target practice (no one send me nasty emails). My son is actually pretty good with a pellet rifle. He sets up at dusk after the birds are roosted and before my nightly lock down. He's got a few kills on his belt too.
7. My husband places rat traps out. They work only for the dumber ones as the others get pretty savvy pretty quickly, but it is another thing that will get some of them. He places either in the wood pile or turns a milk crate over it to prevent dog and chickens from getting into it.
8. And finally we've added poison bait. At some point, you simply have to put out the poison. At this time, I have chosen the repeat bite bait because of my Rattie and the wild hawks and owls around here. The first bite type is poisonous to anything that eats the poisoned rat. The second bite (repeat) is not. While that type does take repeated ingesting before it is effective, it is much better if a dog gets into it or gets a rat poisoned by it.
All we're able to do is stem the tide and reduce waste from the beasties. As stated, we live in an area rift with rats in general. All we can do is try to make our property inhospitable enough and reduce the population enough to keep the hoards at bay.
LofMc