How can I protect coop from rats.

[lynviviana]

I just did a night check to ensure that I locked everything up and all the doors were closed For the safety of my chickens. As I open the door I saw a huge rat run out. What can I do to deter rats from the coop?

 

[raingarden]

https://www.backyardchickens.com/threads/help-me-get-rid-of-my-nightly-visitors.1478593/