I use a galvanised treadle feeder, it has an overhang that keeps the treadle dry. I keep a brick on the top to keep vermin out and stop the top blowing open in windy weather. I have it standing on a pallet with a metal sheet on top of the pallet. This allows the feeder to stay above the grass/mud/weeds, (depending on the time of year) and raising it on a pallet leaves a space underneath to regularly throw in a couple of Big Cheese rat poison blocks where the chooks can't reach 'em!! I put a brick on the treadle to keep it open for the first day but one the gang knew the food was in there they had no problem standing in the right place. You can fit plenty of feed into these units and several chooks can feed at the same time. It is important to clean it out regularly so spoilt feed isn't consumed. I can highly recommend treadle feeders, I wouldn't use anything else.