All this trouble and in the end you are modifying your feeding routine to end the problem and the problem will re erupt after you go back to giving the birds free choice feed. Hanging feeders do not work. A proper treadle feeder with a counterweight, spring loaded door, and a proper feed lip on the inside will fix the rat problem. Howard already linked to my feeder and he was 100% right about following the instructions for installing if you expect it to work and I would add that it is important to follow the assembly and training instructions as well. We have videos up on everything and there are hundreds of reviews up. There is one from a guy that travels with a pack of terriers cleaning up organic farms and he wrote that he is way behind he will recommend they start using our feeders and has yet to visit the place after recommending our feeders as our feeders did the trick.
Remove the access to the feed and stop most of the feed spillage and the rats will find another home in less than a week. As Howard pointed out already, hungry rats will eat rat poison bait so use both methods if you want quicker results.
Most people have no idea how close the average chicken is to disease and death. Read up on poultry disease, most diseases are already present but being held at bay by a healthy bird's immune system. When you stress a bird by moving it or limiting its feed or having vermin around those bugs kick in and can wipe out an entire flock within days.
Follow the instructions. Don't try to use logic with chickens or think you know more than we do about assembling, installing, and training the birds to use the feeders. If you have problems, 99% of the time when people email for help they didn't follow the instructions or didn't understand the instructions. Howard's tip about having it rock solid attached to a wall with the treadle bottomed out on a patio block is the biggest problem people run into. Restrict ALL feed, clean up any spilled feed, no free range, no sitting the birds on the feeder or blocking the door open! The birds will learn once they are hungry.