I finally got myself set up with my first mouse rack. Everything works beautifully, except one thing. My mice have no clue how to drink from the water valves. I've tried leaving them in there for a 4 days to figure it out but they just couldn't catch on so I ended up having to move all the mice to a sterilite bin as I don't have bottles for each bin. I've tried placing peanut butter on the stem of the valve to encourage them to chew on it but all they did was lick the PB off and lost interest in the valve. I got the valves from Reptile Basics. They said they were good for both rats and mice but I'm just not sure if the mice have the strength to move the stem.

Here's what the valves look like:


I'm new to gravity watering systems and I have no clue what else to do to get them drinking from the valves. I'd hate to have to get water bottles for each bin after the money I've spent on the watering system. Any advice and tips would be greatly appreciated! Thank you so much!