I use the vertical poultry nipples. None of my older chicks or younger chicks had much of a problem transitioning to the nipple system. My four Rhode Island Reds were about 8wks old when I finally made the change. For a few days I put their old water in the coop just to make sure they were getting the water they needed. Surprisingly they didn't use the old waterer. Today I upgraded them to a 5 gallon bucket with nipples, so I'm not worried about them running out. Plus they will hopefully won't all four be under one nipple.