Turkey Vultures, like other carrion birds, are protected from disease associated with decaying animals by a very sophisticated immune system.
Unlike most birds, they have a keen sense of smell allowing it to find dead animals below a forest canopy.

There is an important purpose to the vulture's bald head. When the vulture is eating carrion, it must often stick its head inside the carcass to reach the meat. A feathery head would capture unwanted pieces of the vulture's meal, along with all the bacteria such pieces would host. The bald head, ultimately, is a matter of hygiene for vultures.