I was up most of the night trying to find a diagnosis for the issue. There a few pic of blackhead on the web but they may not have that disease not sure. The birds dont exhibit any other symptoms, they appear healthy. they are eating, drinking. New to backyard chickens. It seems all of my australorps have it, my gold laced wyandottes, and black stars. about a dozen bird, 1/2 the flock. they are all 14 weeks old. If you can provide a diagnosis and/or how to treat it, please respond.