Thanks for the mention Debbie292d but I am not the owner of the Feed o Matic or the Grandpa feeder. I manufacture the Ratproof Chicken feeder.
For the OP, the Feed o Matic has an inward swinging door with green plastic parts and lid. The Grandpa feeder is a short, squat, all galvanized feeder with a guillotine style lid, goes up and down over the chicken's head.
Both are made in China although there are some rumors the Grandpa feeder also has a Mexican company making them but I have not seen evidence of that. Last I checked the import records still show the Grandpa feeders coming out of China.
Now, if you would be kind enough to post pictures of your feeder I believe I can help you fix the problem or try to do so.
On the remote chance it is one of our feeders, we have several solutions too so please post your pictures.