We bought a galvanized trough feeder (18") today in readiness for our arrivals later in June. What is the purpose of the blade-like section in the middle of the trough? The top is the kind with oval holes all along the length. Also, would it be a good idea to mount this on the wall of the coop in such a way that is can be removed for easy cleaning? I heard that chickens will poop in their feed and raising the feeder up will help. Thanks.