I have a biig galvanized feeder that ought to keep my hens supplied with constant food for a week. Instead, the moisture in the air is apparently causing the food to clump at the bottom so that once the small amount of food in the tray has been eaten, that's all they have. The top of the feeder is covered and the feeder itself is under cover beneath the coop. I've tried switching feed but every kind available to me does the same thing. Am I missing something here? What do other people in damp environments do? Thanks!