Yes, I'm in PNW too. I'm so glad I have electricity in my coop! I can see needing to use supplimental light year round. Our coop is in a forest area and never gets much light.
Yes, you're right, it's all about their lighting. And I agree with you that at their age they shouldn't start a molt. The only thing I can think of is that when your supplemental lighting goes out the coop or area they are in is still not as bright as the summer months. Also, what type of...