Rodents are the main vector diseases driven and it's important to avoid having them around chicken coops. Knowing what attracts them is the first step in knowing how to control them.
The reason rats and mice like chicken coops is nothing to do with the chickens themselves. It's all to do with the single thing that drives them most - THE CHICKEN FEED.
If your chicken coop also provides a secluded corner that your chickens/cats can't access, the rats might decide to stay for a long time. They will have all in the same place: shelter, feed and water.
Let's start with the first one, the shelter. Shelter for rats is the home where they live and multiply. If you ever did you moved a chicken coop, probably have you found under it, many nests of mice. The best option to avoid such is to have a chicken coop on stilts. Those chicken coops had gained a lot of popularity latest years due to the big advantages they have.
The feed: The main attractant for rats and mice in the chicken coop is the wasted feed on the ground. UpToDate Farmer feeder is the best option at this moment. The 90-degree feeder port orientation + internal reduction makes it difficult for hens to sort out the feed.
If the hens still succeed to make some minimum waste, you may raise the feeder height until the point you see 0 waste but on the same time, hens continue to feed properly. A stand of 23-25 cm high and a diameter less than the feeder (26-28 cm) is what we have concluded to be the best option.
Take into consideration that even are some leftovers on the ground those might be consumed during the day by some lazy hens/roosters. The most important is to not have much feed on the ground when night comes.
Below we have made some tests long ago, placing some cheese in the feeding ports and after two days/nights, cheese remained untouched. We have attracted the rats there using a ground level coop and a classic feeder.
For regions with massive rat infestation we do recommend for overnight protection, the usage of feeding port covers at least until rats leave the area looking for an accessible source of feed. The feeding port cover during the night will completely discourage rats to stay nearby.
However, if the rats remains without feed, won't stay just because they have water.
Hope this advises help and you get rid of rats on chicken coop same way as we did long ago.