I free range chickens and ducks. They all come back to the coop at night but I have rubber tubs, pans, trash can lids and anything else that holds food in them out where they can get to them. I like plastic because I want to be able to get old food out before it gets moldy and be able to clean by using soap and water. The big rubber tubs are the best!
I do not like the really big feeders because I put out too much grain and feed tons of wild birds, wild turkey, possums, raccoons and deer. I try to put only enough for the day so i am not luring in other animals. Though the deer and turkey are okay. Yum!