There are a lot of sites that can help you with ways to get rid of them. They can travel fairly far, getting rid of debris piles, piles of anything really, they hide/live in them, places they can get under buildings, etc can help. My neighbor had an outbuilding that had accumulated years and years of junk and trash. When they finally decided to do something about it, it was full of them. They all moved out and many settled in and around my coop. It sucked. I'd never even seen a rat here before that. I wish you luck, it wasn't something I ever anticipated dealing with. They chewed the crap out of my coop, left droppings and pee everywhere (disease), and they dig. I also had to pick all feed up at dark every night, they were eating a LOT of it. They can find openings where you thought you had none. They will kill chicks, eat eggs, and have been known to chew on the feet of roosting chickens. Ugh! I have had very good results with electric traps for mice, but the larger ones for rats weren't effective for me. They just avoided them. I did warn all my neighbors with cats, and apologized for having to go that route, most of them were pretty understanding, and didn't want to have them moving to THEIR yards. I haven't seen another, or any signs of any, for quite some time now.
https://www.chickenguard.com/the-ultimate-guide-to-keeping-rats-away-from-your-chicken-coop/
https://www.chickenguard.com/the-ultimate-guide-to-keeping-rats-away-from-your-chicken-coop/
