We use one of these plastic 3 gallon red based waterers. It's been working fine for 6mo now. Actually got a second one just a month ago - that way one can be cleaned and drying while the other is in use. Work well, right? For some reason beyond my comprehension, they've stopped re-filling themselves. We have them hung from the rafters (a 5 1/2 foot ceiling height) with chain, connected with an 's' hook between the hook on the waterer and the bottom link on the chain. It seems like the waterer has too great of suction to refill. The hens will drain it dry (or nearly so), I come along for an egg check, notice it's empty, if I bump it or tip it slightly, the whole thing goes 'glug, glug, glug' and refills. But it won't refill without being tipped? If I alter the size of the holes (i.e. trim them slightly larger), will that cause the thing to overflow? If I drill a small hole in the top, will that cause the unit to drain immediately? Anyone else with this issue? How'd you solve it? Thank you for your input!