50 cc's fit in the range (35 to 70) of the data. The sample size was 10 birds, so not a terribly large pool to compare to, but enough to curb some of your worry. Everything's decreasing at this point - their weight as well. They're growing at a much slower rate, shedding baby fat as they fly. And they need less food since their growth has slowed, so don't expect to see him eat an equivalent amount. Watching them lose weight is difficulty, but it's normal. Culturing him for fungal infection seems pretty easy, so if you're worried you should do it. One less thing to worry about... Can you buy a good yogurt there? As you add a bit of vinegar to his water (and be careful with this) try adding some yogurt to his formula. Or mix it into the mixture I described to you yesterday - however you think he'll actually eat the greatest volume of it. There may be some probiotics you could use as well, though I can't recommend any particular brand. You'd want one with many different strains in it - I've heard 10 is a good number to shoot for when shopping for probiotics. If he's been on antibiotics, it may be a good idea anyway. If he needs it, I'm sure the vet has something more effective. Try not to worry - he's made it this far, they're programmed to survive, and you're keeping an eye on things!
Are you planning on ever coming back to the states? 8 years is a long time... Sounds like you're home. But bringing those birds with you... would that be hard?