I tryed really hard to research this before asking, even remember reading a post from someone who had this, but no one knew what it was at the time I read it. His chicken had it on its back, and if I remember correctly it spread and he did loose his bird. I couldnt find his post either. But anyway, my daughter picked up one of our hens this evening and asked "Mom, whats this?" Its the size of a baseball, black,thick, scab of some sort on her chest. Its hard as a rock...can anyone here point me in the right direction in finding out what this might be? Wish the pics could be better, but it was just getting dark, and it doesnt help that she's a black australorp. Thank you for any and all imput!