I have used DDC Veterinary -
www.vetdnacenter.com. They are a little cheaper than Avian Biotech. They have put in rush orders for me, when I overnighted the tests to them on Monday, and by Thursday, I had email results. They also have test forms for the blood tests that you can print from their website, or they will mail you kits. Neither DDC nor Avian Biotech have their species lists separated for just finches, so you have to search thru the lists for your species. And, of course, for the most part they only have monomorphic species listed. I would like to get my Strawberry babies tested, as it takes so long for males to color up, and I believe if I send in blood samples for known males and females, that gives them the 'markers' they need to establish sex.