Here's hjow I feel about it. Unless you know for sure whether the cat is attacking your chickens, you should leave it alone. It does not take long for your property to become a mice resort with chicken feed around. Sure, you can put your feed in metal containers, but how do you stop the chickens from getting some on the ground? Mine are messy eaters despite the fancy feeders. A cat is a great predator for mice. They likely prefer mice to full grown chickens. Once those mice establish in your yard, it won't be long before they are in your house. You know, there is a reason grandma and grandpa had barn cats. I'm sure they didn't keep them around because they were eating the chickens.