I have a single gravity fed feeder in the coop, it's chest high for them so they can't kick out the feed and waste it. I also have a few mouse traps to make sure I'm not feeding anything but them. They eat all they want.Can I ask how much feed you throw yours each day? I have ten that are laying age. They eat whatever they want out side as well as the feed which I don't feed but once a day
For 11 laying hens, I go through a little less than 3lbs of feed a day.
Chicken's need a lot of protein, the 16% minimum was designed for specifically leghorns, who excel at feed conversion) 60 years ago, but today's leghorn and dual purpose breeds need more protein. I dare say 18% is the unofficial minimum now.