Not hard at all for the hens to figure it out, I guess. I was absolutely blown away by how quickly they took to it. I made a nipple waterer out of a 3 gal. plastic bucket (2 nipples) for the run and a 1 1/2 liter water bottle (1 nipple) for the coop (but also left the old water fount in for the night). Hung both late in the day, about an hour before sundown. Figured I'd introduce the chickens to the nipples the next morning after their breakfast. At 8am I turned everyone into the run, gave them their breakfast, and returned to the house to have my morning coffee. I went back out at 9am to do the whole this-is-how-you-get-water-now lesson and found three hens already pecking at the nipples on the bucket. I watched as all six took turns at the bucket. Here I was all worried about making the transition and it ended up that I didn't have to do anything. Now I wish I'd made the switch weeks ago when they were still in the brooder. I, too, hated cleaning out the water sixteen times a day.