I had posted a question re: nipple height. Responders mentioned that they adjusted theirs over time. I came up with a simple solution. From your 5 gallon reservoir bucket, have a feeder pvc go straight down to a "t" that feeds to your horizontal pvc. This is assuming your bucket rests on top of your pasture pen. As the birds get taller, simply put wood blocks between the 5 gallon bucket and the pen roof to raise the height of the nipples. This way you don't have to remove or re-glue any parts.