NW WA is a temperate zone. WA has many microclimates, so precise information depends on exactly where you are. But in general, minimum temps for perennial plants should be no higher than about 10 degrees. That's actually not low enough for my area (around Olympia) where 0 degrees is needed to ensure survival.
WA grows fruit trees well, because we have good chill temps, but fungal diseases and pests can make growing difficult in some areas and some years. The winter chill is good for ornamental bulbs as well, which is why the Skagit area is famous for its bulb industry.
If you live close to the Puget Sound or the coast, you could get mediterranean plants like rosemary to thrive. Unfortunately, I cannot keep rosemary alive out in the garden here.
Gardening in Western WA is very similar, I hear from those who know, to England and parts of New Zealand, and some of the horticultural magazines printed for those locations can be applied for our area, in general though not for every specific location.
Looking forward to hearing more specifics from you.
Definitely plant kale for you and your birds, it's great stuff. Also good are collard and kohlrabi, peas (snap & regular). They enjoy squash so I grew delicata this year and we all enjoyed it. Strawberries are a fabulous NW crop that everyone enjoys. They'll eat most every fruit including raspberries and blueberries. They eat all the apples that fall, too.
Keep your eyes open for varieties that ripen more quickly. We always raise tomatoes, Better Boy and Sweet Million are our favorites. This year they didn't ripen until Sept, but they are always worth the wait in years like 2012. But for my chickens Kale is my favorite, I put it in a suet feeder and hang it inside their pen. They love pecking it.