Pretty much any of the diseases that domestic poultry can get and easily survive can be deadly to a tropical bird that has not previously been exposed to these diseases.
Unfortunately since the change over of the Internet, many online sources are no longer available.
This one has a section on Ocellated turkeys and points out how inbred the captive Ocellated turkeys have become.
Ocellated turkeys contains an error by claiming that no permit is required to bring in the live birds. All states have their own guidelines concerning importing and the Federal poultry import guidelines must also be adhered to. The article does point out the flightiness and failure to propagate.
Breeding Ocellated turkeys in captivity
Due to the difficulty and expense of raising these beautiful turkeys, I doubt that there is much of a market for them. Everyone wants them but very few have the resources to actually be able to keep them alive.
At least one of the places that I recall selling them does not sell hatchlings due to the difficulty of keeping them alive with nearly a 100% mortality of sold day old poults.