I have some doubts about the belief that hill mynahs suffers from this hemochromatosis problem. Especially when it is considered that the favourite food of hill mynahs in the wild happens to be figs, rich in Vitamin C and iron.
I even read that hill mynahs should not be given fruits rich in Vitamin C , not withstanding that they are fruguvorous omnivores in the first place.
I wrote a bit more of that here including bizarre interpretations of giving tea to hill mynahs.
Woes of a hill mynah food formulator // Jackie getting to know me http://shanlung.livejournal.com/133495.html
Why folks tend to think of hill mynahs might be prone to hemochromatosis was explained by me in my findings and accidental discovery on the metabolism of Jackie, my Greater Indian Hill Mynah.
36 Strategems// Metabolic studies on Jackie and first voilational flight
// Perfidious Sieben http://shanlung.livejournal.com/135845.html
Perhaps there might be a lot more hill mynahs still alive in captivity and USA if they have known their demise might not be to hemochromatosis problems.