For you newbies out there, I have never read about this before. My bunnies use a water bottle. I check the water level twice a day. This is my first winter with them. The day of the first cold wave I filled their bottle. At the end of the day the level was about the same. The next morning it was still about the same and I noticed they hadn't eaten as much. This went on into the next day. I thought it was due to the cooler weather, but on the second day my bunnies were listless. I started checking everything and realized that the bottle tip wasn't delivering water!!! My poor bunnies were both trying to drink as fast as they could when I unclogged it!!! I ran and got another bottle and they both drained it half way in one sitting. I think they would have died. I felt so stupid and horrified and sad. Now I always test the water bottle Shen I fill it and if it hadn't gone down, check it again. I just never thought that the nipple on a water bottle could actually get clogged with that little ball bearing instead of automatically working correctly. Duh