Now I've been thinking of this for a while... ;-) It wasn't my idea, I saw it somewhere when we were planning our coop on some fancy chicken coop. It had a 5 gal bucket on the outside of the coop hanging up and it had one of these nipples hanging down with a hole for the chicken to put it's head through and drink. I didn't like the idea of my chickens putting their head out of the coop to drink, I did like the idea of keeping the water OUTSIDE the coop. Now if they had a safe place to put their head to get a drink, that might not be so bad, I just wouldn't want a bunch of water dripping down inside the coop. We raised pigeons for a few years and had auto waters that never seemed to work right and leaked everywhere. We had the waterers out in a covered aviary that could drip down outside and boy did they drip... at least one was always malfunctioning. I'd like to do something like that with the 5 gal bucket and nipple. In the summer you could fill it up and it would last a couple days... longer if you made two! Currently, my waterers are a large pan under a downspout. Always fresh water here in Oregon until it freezes, then we get the heater out.