Here is a gravity fed waterier i recently designed using poultry nipples. I haven't built it yet, so i don't have pictures. First, insert a female threaded pvc adapter with a rubber ring into the bucket. Then get a spout with valve (optional) add thread sealant and screw into pvc adapter in bucket. (depending how it fits, you may need to secure both sides with epoxy cement putty) Then attach clear pvc vinyl tubing to spout and connect it to a three way(or more) pvc splitter. Then attach clear pvc tubing to each outlet and place in coop where you want them. Finally apply rubber cement sealant onto threads of nipples and insert into the tubing. Attach screw clamps for 48 hours or until cement sealant cures. Once dried remove clamp then apply epoxy cement putty around tubing and nipple to keep it secured. Once dried, add water into bucket and let your chickens enjoy! The advantage of using this method it allows you to easily dispense water at different locations in coop while using only one bucket. i built a similar setup that is commonly seen on here where you insert poultry nipples into a long pvc pipe. i have found that i don't like that setup because it took me several attempts to prevent leaking from inserting poultry nipples into the pvc pipe. I finally got it to where it no longer leaks…. So I have come up with this idea as a backup if the current setup fails.