The majority of the treadle feeders are easily pushed open by mice, rats, and ground squirrels or chipmunks. For a treadle feeder to be rat proof you need three things; a narrow and distant step so the short critters cannot reach the feed from the treadle, a heavy counterweight to keep the door firmly closed, and a spring to pre load the door so that even a few large rats cannot gang up on the door and push it open.
Marketing usually wins out over engineering though so the majority of treadle feeders marketed have wide treadle steps. And profits win out over function too so few feeders will have a counterweight or spring load the door. To do a treadle feeder right costs quite a bit of labor and materials and the return on sales generally isn't much. But you can slap together a cheap to produce feeder, spend the money on a pretty box, and give Amazon 30% of the sale and clean up for a few years. The reason is few people actually have rodent or wild bird problems, they just needed a chicken feeder, so they will give glowing reviews and another 20 to 30% will buy the item thinking that having a 50% positive review rating is a good thing.
Do your research by finding independent sites that aren't linked back to Amazon products, and solve the wild bird problem.