"Blackhead Disease Does Not Really Cause Black Heads
By W.R. Davidson
& G.L. Doster
NWTF WILDLIFE BULLETIN NO.25
Histomoniasis is caused by a protozoan parasite named Histomonas meleagridis. Often called blackhead disease, histomoniasis primarily affects gallinaceous birds (chickens, grouse...
I had a feeling you meant that, but I hate to say this, unless they are on deaths door and cyonotic, blackhead does not cause discoloration of the head. :oops:
This is a turkey with blackhead, and next to it is one that died from blackhead.