Do the feeders allow you to adjust how much feed actually comes out into the tray? If not, look for one that does. The kind that we have is put together with springs and nuts on the middle hanging rod. It allows the reservoir to be raised/lowered against the feed tray so that you can limit the amount of feed that actually gets into the tray at one time. One thing with the PVC feeders - they can require some maneuvering to get the feed to come out right if you want to make the trough at the bottom. We use them for grit and oyster shell and love them. But even with using several pieces to make the curve more gentle than a straight 90 degrees, I do have to watch and stick my hand or a rod into it to get the grit to flow back into the trough area every so often. Have had some people tell me that they were never able to get their PVC feeders to keep a consistent flow into the trough. Just something to think about if you are worried about keeping feed available all the time, since they will empty the trough quickly if there is food in there, compared to if you were just putting grit or oyster shell in there.