I have been trying to switch my chickens to the push-in nipple waterers but no luck so far. If I sit there tapping the red part one of them will come over and drink the water that comes out but otherwise they are not interested. I was looking at other types of waterers and I saw these ones http://www.meyerhatchery.com/get_item_4449_universal-pop-bottle-water.htm and I also found some that are cast aluminum on the Stromberg's site. Who has tried them? Do they leak? How long do they last?