These cups work terrific. There is confusion in other reviews about the cups NOT refilling after the chicken drinks the water. This is how they work: Chicken pecks at the yellow water trigger and the water flows into the cup, chicken drinks the water. The cups do NOT just refill because they are empty. They are not supposed to. Another chicken comes along, pecks at the trigger, water flows out and they drink the water and then walk away. You may periodically find water left in the cups because the hen did not drink it all before walking away. They only release water when a hen moves the trigger. Not when the cup is empty. Hens will learn where the water comes from and activate the trigger as needed. They do work and they work terrific.

I bought this product initially thinking it was a float system in that so long as water was available to the assembly, the water level in the cups would remain full until the chickens drank down the level, thereby lowering the float and opening the valve which would allow more water to enter the cups. Well, I was wrong and this is definitely not the case. The yellow stem has a spring on the cup side which holds tension on a rubber O-Ring that's attached to the yellow stem on the back side of the black fitting. So in theory, when "bumped" by the chickens the yellow stem is supposed to cam slightly breaking the O-Rings seal against the black fitting, allowing water to dribble into the cup. It does not work effectively. Unless your chickens grab the yellow stem, pull it up, and hold it there for about 5 seconds, they aren't going to get water. I had four cups screwed into a 5 gallon bucket, and tried varying depths of water over the course of a week from barely above the cup lines at the bottom of the bucket, to as much as 2.5 gallons, but all four cups yielded the same results... always empty. Even manually filling the cups for the chickens was difficult, as pressing down on the stem did very little, and I had to pull up to get any appreciable water flow. These were horizontal mounted, and all troubleshooting, and cleaning was performed. I am abandoning the cups and will try the water nipples as an alternative. I hope this review saves someone the wasted time and disappointment that I encountered.