I forgot about that question. DH made a horizontal nipple waterer from pvc pipe (maybe 4"?) and attached a few nipples along the bottom of it. Found that the length didn't hold enough water, so we put a 90-deg elbow on the end and ran it upward, the another 90, and more pipe to hold more water. The chicks use it pretty well, but I still have a regular gallon waterer in there too, and they use it too. I'm scared to take the regular one out, because I don't know if they "all" use the nipples.Ditto that question. Who uses vertical nipple vs horizontal nipples?
You can see it in this pic. The nipples hang down for the lowest horizontal section. I can fill it from outside the run. Its needs a view window though! I just keep it full, because once it gets below the fill point, I can't tell how low it really is! lol