Welcome to BYC!We Live in North Central Oregon. It sounds like our winter temps. are similar to yours. Did you figure out your system. My husband is convinced if we come up with a system the the water is able to run through the whole time, it won't freeze. We are on a farm and are going to run the water out to some trees that could use the watering. So that it will just pass through the coup and always be fresh for the chickens.
Looks like @mrmojo08 is no longer active here....not since 5-16.
Running water 24/7 seems wasteful (trees don't need that much water) and no guarantee it won't freeze depending on temps/flow/etc.
Also posted this here:
https://www.backyardchickens.com/threads/diy-chicken-waterer.1250728/