Chin in the wild are not drinking from sitting water sources where a dog that has recently licked is own anus has drunk either.
The mountains where chins come from are pretty much deserts, so no they don't get drenched often.
^ agreed. However it's also been said many times that chins have been domesticated for so many generations that our pets are a far cry from those in the wild. Our pets would not be able to survive in the wild.
I also wonder that perhaps even though you can get their waterbottle to work, perhaps they are having issues with it? Have you tried getting a different bottle and putting it on their cage?
This happened to me earlier this year. The bottle would kind of work if I manipulated it, but Lily could get it to work. I had to buy a new bottle for her. Now, per a forum member's suggestion, I keep 2 bottles in the cage incase one stops working.