If you start them with the horizontals, they should be fine. That is what I did after about a week with a more open waterer... Vertical ones drip...teach them by tapping the horizontal nipple and there will be a tiny bit of water in the cup. If you "peck" on it with your finger, they will get the water and get the idea to peck. Helps that the nipples are red, of course! Once one of them gets it, they all will..shouldn't take too long. That is how a mother hen teaches them i think, by pecking. I call mine over for treats by pecking a stone or wood decking with my fingernail...they come a-runnin'!