My wife took our dog out the garden she heard a noise in the coop when I opened the nest box one of our polish frizzels had been bitten all over mostly at her back end she was 2 far gone to save so I have caged the rest of the flock and brought them into my garage overnight will look at the coop tomorrow to see where they are getting in could not see any holes I hate rats. The hen was so friendly she would always come up the garden when called my wife is so upset. this is now an all out war I think I know where they are living war starts tomorrow after I find where they are getting in and try to stop it.
Bad news! Rats can squeeze through a very small hole. I found this:
http://www.victorpest.com/advice/tips-and-strategies/how-to/catch-a-rat
with a quick "rat trap" search on Google. Surely if rats are a problem in England, such devices must be sold there.