Put your feed in metal trach cans to help reduce thir food and cause them to move on
Like I just suggested to another person:
Be cautious of the poison or traps because a chicken will peck and eat a dead anything! How about using a open top barrel about half full of water, drill 2 holes opposite each othe in the rim, stretch a piece of coat hanger wire across the top of the opening using the holes to secure it, hang a tasty bait in the middle of the wire, and lay a couple ramps from the ground to the rim for easy rat access. The rats will climb the ramp and try to reach the bait, fall into the barrel and drown.
low maintenance, multi animal holding, non-poisonous, and no touching the rat carcasses. WIN WIN WIN