A while back (around 1 month ago) i noticed that 1 of my 3 white leghorns had developed a bump sort thing on the top of its beak. At first it was small and wasnt black, but now its getting bigger and it is starting to turn black on the top. What is it and what should i do. I haven't seperated it yet because none of my other chickens are hurting the Leghorn. Is it poisonous? Is it urgent? WHAT SHOULD I DO!