My girls are just now 21 weeks old and I got my first eggs starting 1 week ago from my barred rock Artemis. My coop and run are in very dense shade from a mature douglas fir and a big old dogwood tree this time of year. The run gets about 1 hour of partial sun in the mornings. My other 2 have not yet started laying.
I don't know if this will affect production in the long run, but I think it's hours of daylight and not direct sun that influence their laying hormones. The only thing you may need to worry about is Vit D. Apparently chickens need it, too. As in humans, it is produced by exposure to sun. You can supplement a human orally, so maybe there something you (and I) can do to increase Vit D, because physiologically it's very related to bone growth and density.
For what it's worth, though, Artemis' eggs are MUCH harder than grocery store eggs so far. I'm interested in others' opinions/evidence on this.
Sonya