We had some furry friends in our garden about 2 months ago, the kids have rabbits and the rats were going in to the rabbit hutch and taking the feed. It didn’t help that we have neighbours who feed the birds
and a stream not far away.
I secured the rabbit hutch as best leaving an access point under the hutch which the rats used. I put sachets of poison near the access point, I also put 2 baited traps and 2 bait boxes down along the building line. After about a month there was no further evidence of any unwelcome visitors, the poison under the hutch was taken as was the poison in the bait box, but the traps weren’t touched.
You can either get a pest control guy out or do it yourself. If you’re using traps, cut a small hole in a box so the rats can get in and bait and set the traps, after about a week they may show an interest. Doing this prevents cates and dogs etc getting hurt. Rats are neophobic and avoid things which are new to their environment. Alternatively, use poison. Buy bait boxes and poison and put them out. You should check the area around the house every days and remove and dispose of any dead rats safely - if you don’t there’s a risk animals feeding on the rats could be poisoned too.
The best poison to get is the 1 feed stuff, but access is restricted to pest control pro’s, people like farmers who have a farm assurance certificate, or people who’ve done a pest control course and got the certificate - it’s about £75.If you know the farmer, have a word maybe he can assist you. I bought poison from the local farmers coop, it was multi feed poison so they needed to eat it more than once - I wasn’t able to source the really strong 1 feed stuff. Alternatively, you can buy the poison on line. I think I bought Sapphire.
Do some reading up on line and look for rat runs. Good luck.