I am celebrating that my youngest (who are now about 12 weeks) are FINALLY heavy enough to work the treadle so no more having food out or propping open the treadle feeder. Just in the last week of having no open food there is already a noticeable decline in rat presence (which resurged a bit in the last two months with available free food).
If your chickens get along, I have noticed that my hens will sometimes eat together, so that the littler hens know to go eat when the big girls lower the treadle. You can adjust the spring on the feeder to make it more sensitive to open. Obviously you don't want it so sensitive that a rat can operate it, but you can mess with the settings so that your little one can get in.
I already said it, but I was calling my situation "Nightmare Ratatouille." Just so awful. I could post pictures that would make the hair stand up on the back of your neck.