I have a rooster with a cross beak problem, and he couldn't eat out of normal chicken feeders.
So I developed a special feeder from him, that would probably solve your problem too.
It's a very simple feeder to "build."
I just take a clean, empty, #10 can (the size they use in schools or even large families for canned vegetables; coffee used to come in a #10 can but I'm not sure it does anymore) and I fill it up half way with sand or very small pebbles. This weights the can down to keep it from moving around when chickens eat or knock it.
Then I fill the upper half of the can with chicken feed.
My cross beaked rooster can eat out of this feeder because he has plenty of room to scoop up the feed, without the feeder moving while he scoops up the feed the best way he can.
I noticed that the other chickens seem to prefer this tin can feeder to the feeding strips with the 16 holes that I bought at the feed store. Every now and then, they knock the feeding strips off the feeding table, but they NEVER knock that #10 feeding can over.
If you don't have a #10 can, go to your local school -- they will have plenty of them there, and will probably give you how ever many you want.
If you can't get one any other way,
WalMart has a special section where they sell industrial sized (ie, #10 cans) canned foods. Alot of people who run day care operations in their homes buy these, as do families with lots of kids, so every
WalMart has an area like that. Just buy a #10 can of your favorite food, even if it takes several meals to eat it all.
It won't be any more expensive than buying a specialized chicken feeder, and might just be less.