Fowl pox is a disease that occurs worldwide ... The diphtheritic form shows cankers or yellow lesions in the mouth, esophagus or trachea. Other symptoms include blindness, feed refusal, lowered ...

In your case, from what you have presented, I highly suspect fowl pox infection ... sign of this disease is presence of wart like lesions on the surface of the skin of the head, comb, wattles ...