I've been keeping chickens since 2009, and had just learned to accept feeder waste. Other than one homemade bucket feeder (which allows for very little waste due to how deep the dish part is), I've always used the store-bought red/white gravity feeders, and have often wondered WHY they make the dish part of the feeder so shallow - allowing chickens to easily spoon the feed over the edges!! Maybe the same company who makes chicken feed also makes the feeders, and appreciates the waste more than I do...lol! Anyhow...I simply wrapped a border of 1/2" cable wrap around the perimeter of the dish lip. It's probably called something else, but its that sliced plastic tubing that helps keep wires bundled together - my mother uses it over her oxygen tubing to keep her cats from poking holes in the tubing. Thanks to the precut slit, it goes on easily. And its worked!! Before, my big girls could empty a newly filled feeder in an afternoon, with crumbles heaped up on the ground beneath the hanging feeder. I started using the cable wrap about three weeks ago, and the feed is staying IN the feeders!! Because the edges are rounded, including on the inside of the lip, they have a difficult time pulling the feed up and over the lip. I did find it starting to come off a bit where the joint is, but overlapped the ends and that seems to have fixed that issue.