Had a 2 yr old leghorn die suddenly. She had a loss of feathers on her back, which I thought were from being pecked or molting or so I thought. Yesterday I applied Peck No More. Then this evening have found her dead In a laying box. Did not appear as if she had been sick. She has a black substance that I noticed yesterday, on some of the feathers that are left on her back, it looks like a tar substance but it’s not sticky. I have no idea what this might be. There is nothing in the pen that could secrete a substance like this. Note the pens 12 + years old. Never had any other unexplained deaths.