Start the chicks as soon as possible on the hydrating bucket. I started my chicks at two weeks. For two days after introducing the watering nipples into the brooder, I continued to offer the original water source (inverted Mason jar in saucer-type dish). I watched the chicks to make sure that each one had used the nipples several times, and once I was comfortable that all of them were drinking, I removed the original water tray.. Originally, I used a small food-grade Hershey's cocoa can to hold their water with just two nipples as my first attempt to introduce watering nipples, but the container did not hold enough water for 6 chicks for a day. So, I bought a small pail (a 1 gal. size) for under $3. I put 4 nipples in the bottom and secured the pail over the side of the brood box with a cord. I put a mark on the pail to monitor the amount of water being consumed. I appears that 6 chicks are consuming two full cups of water a day. I watch them a lot to be certain that every chick is drinking and that none are showing signs of dehydration. You should have great success with nipples for watering if you start them on a hydration bucket. I don't know anything about a using a PVC line with nipples from either a hose or rain barrel, but YouTube has several videos made by people who are doing it successfully. You can buy a 3 gal. hydration bucket that comes with a lid, water cap, and four nipples for about $15, or you can make you own for a lot less if you have a drill, 3/8" drill bit, a pail, and a pack of watering nipples (usually about $4 for four nipples with silicone washers attached).