Rats: What finally worked for me.
Been seeing lots of posts about rat infestations, and I can sympathize because we had a pretty out of hand rat situation here too. So I figured I'd share my very expensive trial and error lessons I learned - what worked and what didn't.
Sealing house entry points: this is a MUST. You will never get rid of them all from your house/walls/garage/attic/basement until you seal off every last way they can get in.
Hot pepper flakes mixed in with chicken feed: chickens enjoyed it but rats didn't seem to care, they just ate around the red flakes.
Grandpa's chicken feeders: does a great job of keeping the rats out of the food, unfortunately it also keeps the chickens out. My chickens hated it, and I followed all the instructions for getting them used to it, but they can't stand being near it, they'd literally rather starve. I still use it but I have to leave it in the locked-open position during the day time or my chickens won't eat. But at least I can close it at night and the rats stay out.
Poison: did absolutely nothing. Rats never touched it.
Ultrasonic repellers: seemed to work for a short time but after a while they ignored it.
Bucket traps: not one single rat caught.
Snap traps: these worked pretty well. Both the traditional wood ones and the newer plastic ones, worked about equally well. The problem is you only get one per day per trap, and if the others see rats dying in traps they start to avoid them. I got a few dozen with snap traps but it never seemed to reduce their overall numbers by much.
Ratinator live traps: these were recommended to me here on this sub. I bought 4 of them for a pretty absurd amount of money. After a month I have only caught 3 rats in them.
Pellet gun with a scope and a flashlight: this is way more fun than the above methods, but it's very hard to get any to sit still long enough to shoot them when there's a flashlight pointing at them. I was able to get half a dozen or so, but most times I went outside to hunt them I didn't manage to shoot any.
Pellet gun with a thermal optic: expensive, but a total game changer. You can shoot every single last rat you see. It's basically cheating. You see a glowing red rat, you line up the cross hair, pull the trigger, dead rat. Virtually every single time. You can scan your whole yard and spot every last exposed rat in seconds, without them even realizing you're there. It was so effective that I was almost sad when I ran out of rats to shoot. I still see one here and there that wfinds it's way into my yard, but it's no longer an infestation of hundreds or thousands of them. The nests are abandoned, they're not living here full time anymore.