You both make good points. I guess I'll start bringing in the kids for a yearly physical, get x-rays every couple of years on the ones who are tough enough to get x-rays (there's one or two I wouldn't have x-rays performed on because they'd probably go into shock from overreacting)...as for blood work, I don't know. In my experience, there's not a whole lot of tests they can perform due to how small my kids are. Noah, Rosie, Starlight, Trixie, and Rainy would probably be safe to take for blood work, seeing as they're all younger and are quite brave and/or healthy. Meanwhile, Alex has chronic health problems and is really old (he's arthritic, has severe asthma, etc.), Lara hasn't been doing well (she's nine or ten, has an atrophied preen gland, had to have an episiotomy because her cloaca was too small to pass poop and she also had eggbinding, and she's had cancer in her hip and abdomen for the past three years), Sunshine is yellow so she bleeds and bruises really easily, and Birdie is too frail (she has anxiety attacks, bad liver disease, a huge tumour; please note that it's her previous guardian's fault, and I've shrunk her tumour down by at least a third with dandelion root extract, and I'm treating her liver with milk thistle seed extract).
Having physicals and x-rays performed at my local vet wouldn't cost more than $200, I don't think, but blood work at the Bowmanville vet an hour away...I'd have to pay a visiting fee, an additional fee for each bird they haven't seen before, they'd probably insist on doing a physical which would cost more money, then they'd charge me to draw the blood, another charge to transport the blood, then a charge for each test they do on the blood. So five birds...almost $800 to have blood work done. I think they might give discounts for bringing in an army of birds at once, so maybe $650. If I'm gonna pay such a ridiculous amount of money while living in a country with universal healthcare (non-prescription related medical expenses are a foreign concept to me), then I guess I'd rather make a whole trip out of it and go see Tiki and Ria's old vet all the way out in Toronto. I've seen five different exotic animal vets over the years (exotic vets are fairly new here in Canada), and Dr. Morris (local, very inexpensive, compassionate, performs lots of procedures for free, but limited in what procedures he can perform) and Dr. Yee (expensive, but I really like her and she really cares about and values the birds I bring in, no matter how old/inexpensive/small they are).
As for keeping track of their health, I don't think it's anything particularly special. I just remember how each bird typically stands and holds their wings, the colour and shape of each toe, which nails always grow too long, the colour/shape/and imperfections on their beaks, where each of Trixie's deformed feathers are from her polyfolliculitis (it makes it easier for me to remove them), etc. Whenever I see animals out in public, especially fish, I can tell you right away whether or not they're healthy. It just comes naturally to me.