I have two of the feeders I mentioned for 17 adult hens, and I only have to fill once a day (and they are not even all the way empty).
They still scratch the ground in front of the bowls when I feed them by instinct. It's funny to watch.
I have been trying different things learned on this forum. I am aware that one of the members makes a great PVC pipe feeder, too. But here's my solution. I have one of these cheap feeders with the jar attached. And I put it in a cheap dog bowl I bought from Walmart that it fits into exactly...