These links may give you ideas. I have 2 for my 26 chickens. I use the 2 gallon buckets with the oval holes cut into them like the "feeder bucket with holes" photo. The food grade buckets were free at my local grocery that has a deli.
I have one bucket feeder for 17. I don't have a picture but I cut out horizonatally and that way I can get maybe a gallon of feed in them. What I like about the bucket feeder is they have to stick there neck inside it to eat and they can,t get there feet in it to scratch it out all over the place. Much less waste.