Well, Mateo had his vet visit today. He's put on a little weight, it seems, and now weighs in at 92 grams. This is good news!
In regards to his baldness, I discussed the possibility of something fungal. While it might be the issue, we don't know and to test for it, we'd have to take a chunk of Mateo's skin and send it away to a lab somewhere to be biopsied. Though I didn't have a problem with doing that, my vet told me there aren't drugs/medication to treat for fungal issues specifically in cockatiels/pet birds (is that actually true?). Plus, even if we were to attempt it, like BostonBudgie said, it can be toxic to them and can compromise their health/liver functioning.
We then talked about lutinos and how they're so far removed from the "normal" normal greys of the wild. They are a little more prone to genetic deficiencies due to all the inbreeding that happened long ago (kind-of like dalmations and blue budgies) and Mateo does indeed have the bald spot behind his crest.
Mateo's diagnosis? Baldness. My vet suggested that I just learn to live with it and enjoy Mateo the way he is. After all the reading, research, tests, changes and forums I've been to, I'm inclined to believe this is the way to go. Mateo's health is good, his quality of life is good and he's happy. He's not picking or plucking, the area isn't irritated and the skin that I can see is normal (the vet is in agreement).
Mateo's protein level was a little low (but the rest of his bloodwork came back OK), so I'll continue on with the Lafeber powder added to Mateo's food. The vet did also mention this might be an allergy. That's something I may look into once he's well on his way with Harrison's.
I know not everyone is going to agree with the vet's "diagnosis" or my agreement with the vet, but I feel I've done all I can for now. Mateo IS happy and his health is not in jeopardy. I feel good about that.
