I contacted the Oregon state wildlife vet (he was AAWV president at the time) when I was planning my externship to ask about which state wildlife agencies took vet students. Several of them don't advertise their externships, but can arrange something if you contact the state vet. I wound up going to Idaho (was interested in working there after graduation), and spent my 2 weeks there doing lots of necropsies, helping with the lab work for some ongoing projects, and capturing sage grouse. We were supposed to do deer and/or bighorn sheep capture as well, but the weather wasn't cooperating. They also arranged housing for me within walking distance of the office. Most of the state vets will try to schedule externs when there is capture work, but plans tend to change at the last minute based on department needs, weather, staff/equipment availability, etc.