I'm guessing you don't have woodchucks (groundhogs) like I do! That gravity feeder would be empty in a day. I had to take to raising the hanging feeder way off the ground (no the chickens can't reach it either) if there was any food left from the night before. The girls can go outside any time they like after I open the barn door in the morning so they are out hunting vegetation and bugs all day anyway. Then the wild birds (who don't eat all that much) and the chucks would come clear out the feeder. So bizarre, the domesticated birds are all out foraging food the wild animals SHOULD be eating and the wild animals come into the barn to eat chicken feed.
Occasionally we have squirrels. I'm sure that we will get more critters visiting once they know chickens are here, but aside from the coyotes in the area, living here for five years, I've never seen a raccoon or a possum. Lucky, but I don't expect it to last.