Here is the feeder I just built the other day. I wanted a feeder that would sit in between the studs in the coop I just built so it doesn't take up too mush room. I also wanted a "window to keep the levels in check and the birds happily fed. It is 33" high, 12" wide and 3 1/2 inches think. Painted to match the coop interior and installed 2 latches so I can remove for filling and cleaning etc.. All materials were acquired for free through craigslist scavenging (except for the 2 latches that hold it in place).
Here you can see where I angled the food towards the dish and the "plate" I made to try to keep them from scratching it all over the place. (later I cut the holes out to make 1 large oval to let it feed right) They didn't have enough room to peck at it and let the food tirckle down correctly.
Here it is before the glass piece was slid in, ready for a trial run.
Here it is installed but missing the plate, with them pecking around the dish it fed down the shoot great.
The oval plate (not pictured worked great, little spilled food and helps to keep them from walking and pooping in it)
It pops right out for cleaning and refilling, enough food for about a week for 4, 10 week old birds, 2 red star, 2 black australorps.