I don't know about Washington, but here in Texas, and where I'm from in California, fallow deer are fairly common. Willits CA has them all over the place with allot of resturants and business using the white deer theme. Sometimes you can see them while driving along the highway, and allot of times, I'd pull over on the side of the road to glass them with my binoculars. When it's lush and green out, they really show up good!!!
There is also quite a few of them running wild at Point Reyes, on the coast just North of the Golden Gate Bridge. For fun, I used to go for hikes there to try and find them and take pictures of them.
Hurst brought them to his place and they are still running wild all over that area of the state.
Here in Texas, they are very common. There's no telling how many have escaped high fenced ranches, but under fence, there's tens of thousands of them. Some places raise them for venison like cattle. Near where I leve, there is a program at the Ag Extension on deer farming with fallow deer. There are two ranches that raise them in my area that I know of. Sometimes we drive by one of them to take pictures of the bucks.
I've been to the auctions and can buy yearling fallow bucks for $300 each. I've seen lots of three go for $500 for all three!!!!
I can't verify this for fact, but George Washington is credited with being the first person to bring exotic wildlife to the country. He brought and released fallow deer on Mt. Vernon. The estates in England have been breeding and raising them for centuries. They are considered to be the easiest of exotic deer to raise and naturalize to local conditions.
From the picture, it looks like a fallow deer. They can be raised as bottle babies and become very tame. Some are just used to people. I'm guessing that it was a pet and wondered off.
Eddie