I don't know enough about either Oregon weather or parakeets to answer. I was assuming your birds were only going outside some of the time.. The Catoctin Zoo, north of Frederick MD, has an enclosure full of 'keets. I know they aren't out there in late fall and winter, but I don't know at what temperature / forecast they are taken into their shelter. You might get in touch with them for advice, if you can't find a local person with experience... hmm, maybe there is an aviary near you that could help?
