Just buy a Grandpa's feeder. They work like a charm. Don't waste your time and energy on cats, traps, voodoo spells or whatever. I have one and everyone I know to whom I've recommended one has reported back the same result - no more rats!
We have two Silkies that we have to re-home. One is ca. 9 months old, the other ca. 6 months. Photo below
. The are in Oakland California. I don't know about costs or methods for shipping.
This silky chick, "Goldie" turned out to be a rooster. Good-looking, but noisy. With PST coming back, his early morning crowing is getting to be a problem. He needs the country life - and soon.