I'm wasting no time with the birds I just purchased, I'm taking them to be tested as soon as they can fit me in! I'm not letting them near my sweet birdies I raised from chicks until I know they aren't contagious. It's such a shame. I'd rather see them euthanized cheaply by the state then watch them get sicker and suffer if this isn't just allergies. I figure if the state finds something, I'll report it to the birds original owners and caution him to cull any birds that are sneezy instead of taking them to auction. Currently I have them both on duramycin, and medicated chick feed, and I poured ivermectin pour on wormer, and so far the yellow goo is reduced in their nostrils, and less sneezing, so we'll see. I'll have to buy some yogurt next...
I wish you luck with your birdies. I would be doing the same thing trying multiple approaches to nurse them back to health, but I would have my husband dispatch them if I saw they were in real pain just trying to breath- since it just tears my heart up to see them suffer. My chickens are really my pets, and I'd rather end their suffering quickly than let them languish in pain.
*hugs*