toss them some cut up cucumbers and melons for them while they're learning the nipples. lets them get some extra water into their systems.We just got our nipple water system up and running today. I read that you should take out any other water set ups so that they will use the nipples. I hope that was right because i feel so guilty taking out their old water bottle, but the nipple system holds so much more and will be so much cleaner.