How old are your chicks? You say they're too short to reach it...have you tried lowering it so they can? I use the horizontal water nipples and was literally dreading trying to get them converted over for fear "my ladies aren't drinking!" But I was determined mainly because the thought of continuing with daily clean-outs and refills of the old-style waterer was gettin' OLD....really OLD.
So one day I said "this is it girls, you either use 'em or else" .... I REMOVED ALL OTHER WATERERS....all of them. I sat in the coop "clicking" the little stainless steel thingie (for what seemed like forever!), and finally one of them, out of curiosity more than anything else, came over to see what all that "clicking" was about. She put her little beak to it and voila! THE REST IS HISTORY! They all got curious and that was the end of the messy old-fashioned waterers.
Be persistent!! Never give up!!