For us the rodent traps worked great, we have had no rodents digging under the coop and we have had no rodents in our backyard at all. A great way of getting rid of both rodent and rat is to keep the grass cut short. I would suggest putting rodent traps out and keeping the grass short instead of installing something. There is another way too. If you were to get a roo that would most likely help defend the hens against snakes and rats too. They could also give you a lot more benefits such as alerting the flock when danger is near and defending the hens with there life, they can also give you the fertile eggs but if you don't want fertile eggs you would just put them in the fridge for a day or so to stop the progression and so you can eat them. Now if you live in a area where you can't have roosters you can 1. Get a rooster collar: people do not like the collar because it supposedly is abuse to the animal, but it is not. If you apply it right then it will make the rooster quiet and make it so you can keep it. But you cannot tighten it too much, you should be able to get a pinky through the collar. There is no evidence that the collar is animal abuse, the roosters get use too it and end up living a happy life. 2. You can blackout the coop which quites the crow in the morning. Now that Is all if you want a rooster, you might already have one. So 1. Set up rodent traps 2. Cut the grass short, don't let it get tall 3. Get a rooster (optional). Note: (If you decide to get a rooster you should still do 1 and 2, but like i said before the rooster gives you extra benefits and extra protection.)