I have neverheard of a vaccine for it. Look at http://www.oznet.ksu.edu/library/lvstk2/EP69.pdf or
http://www.msstate.edu/dept/poultry/disproto.htm (scroll down to middle of page for blackhead) or
http://www.worldpoultry.net/poultry_blackhead/ or
http://www.dapdegussem.com/certificaten/Clark Flagellated (WP 2003).pdf (look at 'Histomonas' section, that's blackhead)
for more information.
Certainly people do sometimes mix chickens and turkeys without serious problems, so it probably kind of depends what your risk tolerance is like.
Pat
http://www.msstate.edu/dept/poultry/disproto.htm (scroll down to middle of page for blackhead) or
http://www.worldpoultry.net/poultry_blackhead/ or
http://www.dapdegussem.com/certificaten/Clark Flagellated (WP 2003).pdf (look at 'Histomonas' section, that's blackhead)
for more information.
Certainly people do sometimes mix chickens and turkeys without serious problems, so it probably kind of depends what your risk tolerance is like.
Pat