My feral cats keep all rodents away but in the past when we had a rat problem, like you the problem was already here when we moved in. If I couldn't take care of it naturally, ONE BITE does work. I let go of the concern that a cat is going to actually eat a rat and then get some of the one bite through the rat. Cat's do eat moles and mice but rarely rats. So I just seriously doubt it will go from one dead rat to another animal as long as you put it where only a rat can get it, not a dog or cat. Like under my coop foundation which is low. Rats take it back to the nest and everyone dies. Knowing that they go looking for water, I placed a bucket of water close to where I knew they were coming from and checked it quite often. I only had to do this once to knock down the population because they ate my hot tub and truck! After the ONE BITE took care of them, the Feral cat's have detoured any newcomers for many years.