Lobstrosity, I think in your area you could grow vines and apple trees very well in your area. You sound like you have a good set up for your birds.
We are in No. Ca., and "Anna's Apples" grew HUGE and delicious here, and also very quickly. We hope to find more bareroots as they are inexpensive, but they do take a few years to fill out. Definitely try different varietals as they ripen at different times. No citrus though, bad for chickens. Also, chickens love strawberries too (they are perrenials), but they dig up the plant too much to keep them in with the chickens. The mint is a surprisingly great and easy addition that comes back every year- especially good in late summer when much of the garden dies down, and the chickens always smell good too.
We supervise free range our 85 chickens (plus supplement feed, garden items, scraps and treats) too, and as a general rule they all still come back to the coop at night. Occasionally, we've had a straggler who stays out later than the others, then has a hard time finding the way back due to their poor night vision, so we always check (especially at disk), then always do a headcount as predators (especially ravens) are always an issue to be aware of. Our nest boxes are in the inside henhouse's wall, accessible from the outside of the coop. The girls had secret nests at first, now everyone lays in the henhouse after we put golf balls in the nests.
We hope to expand the garden this summer. Add more Kale/ brocolli, snow peas, carrots, squash, pumpkins/ watermellon/ tomatoes- they love it all. Also, cover crops to rotate.