Yes, I have. And after monitoring them, I know for sure that my birds don't drink as much from the nipples and that they drink much more if they have water available in a regular waterer.
Honestly, my opinion is that if I can provide water for them in a regular waterer, I choose to do that. I think it's better for them to have more water for their health.
Thanks for the honest input.
I installed the water nipple system to make it a lot easier for me to add water during these cold months. It has already reached single digit temperatures a number of days and having to carry the "gravity" waterer outside of the coop to remove the dirtied water in the lip as well as add more water without getting myself and the coop all wet and frozen is not fun. The nipple waterers have eliminated this problem, but I know my chickens aren't drinking the same amount and it concerns me.
During the winter months the only water source they have is inside the coop because that is where the electricity is, but when it has began to thaw out again periodically, I will see them drinking a lot from the puddles of melted snow and roof melt. Another thing that I don't like about the gravity waterer is that my leghorns and other birds with longer combs and wattles seem to get wetter, which also causes problems for them in very cold temperatures.
I am still torn right now about what to do. If I could be convinced that the water they are getting from the water nipple system were sufficient enough for them, I would be satisfied. Right now, I am not sure, though I don't seem to see any of my chickens dying of thirst either. I am not exactly sure how one knows, though.
I also wonder if I had started them out sooner (like when they were chicks) with a nipple water system, if it would seem more natural for them and they would be drinking more.
I will continue to monitor the situation, Obviously, the health of my flock is more important to me than the inconvenience of changing out their water.