I've been using the little push-ins...I settled with putting two on the lower side of a Trader Joe's Ice Tea gallon jug opposite the handle, that way I can sit the jugs flat when I am refilling them instead of having them sit on the nipples and having it leak all over, and then I hang from the handle at a slight angle. I also drilled a couple of air holes near the cap, not sure if it's really necessary, but I have noticed there is no black stuff (mold, mildew, upchuk?) any more. I have had leakage occasionally, not sure if it's from my inexpertly drilled holes... now I use silicone caulk around the little collars. I made about six of them and switch them out for my six hens weekly and as needed, have one inside, one or two outside. I use water with ACV. I am very satisfied with the system. The grils had no trouble figuring out how to use them. I got a pan-style heated waterer for winter, but the girls seem to prefer the nipples, just take a swig or two in passing and move on...