What all blood tests do you do for your birds if any? What should we be telling new folks? I am currently looking for a new avian vet in my area as well.

all of my birds are tested for beak and feather, polyoma virus and psittacosis. gram stain and fecal are optional depending on the conditions that the bird came from. I also randomly test my flock yrly to make sure no one has anything that didn't show up in quarantine.
there is also a vaccine against polyoma virus- I do not vaccinate against it- reason being- if I did - then my babies would test positive - is it because of the virus or the vaccine- i'd never know.
so if I test and everyone is neg- then if I get a positive- i know it's the true virus.

I always recommend a complete blood count, blood chemistry, psittacosis test, fecal and fecal culture. A Psitticine Beak and Feather blood test should be considered as well. It never fails to amaze me that some owners will spend a great deal of money on toys and cages, yet, scrimp on a physical examination and diagnostic work up to ensure the health of their pet.