Gravity feeders have no batteries to replace, no controls to freeze up and will not waste feed. When the feed on the ground is consumed, only then does fresh food come out of the feeder holes. Works equally well with whole corn or cracked corn. Aunt Molly has kept these empty barrels out of landfills by turning them into useful products for homes and gardens. Although Aunt Molly"s barrel products come in many different colors, they are all VERY GREEN products. Go Green, by purchasing recycled products.