I'm in the Cascades of Oregon, a California transplant (aren't we all?), and I love it up here. Except the Winter does last a LONG time -- a really long time. I've been in Oregon for 11 years, and I start dreading the Winters sometime around the end of August, only because I know the beautiful weather will be gone in two months, replaced by constant wet and grey.
The Oregon coast actually has more sunny days than the Willamette Valley, so maybe Seaside and Astoria won't be that bad? I dunno. Just be prepared. Those "happy lights" are only $30 at Costco. You and your chickens might need it!
One thing no one told me before I moved to Oregon, it gets really cold here too! Everyone talked about the rain, but no one said, "Oh, yeah, it snows, too!" When I moved, I didn't even own a windbreaker! Now I have parkas, wool coats, snow boots, rain boots, and of course, two pairs of Uggs, which have NEVER gone out of style in Oregon (Summer or Winter).
I could never have bought a house anywhere but a homeless camp in California on a teacher's salary though -- so I can deal with the rain and grey.
Good luck!