Hello, I came home from work to one of my five hens dead on the coop floor. She was on her back. I was checking her to see what would have happened as she was not sick and bowed no abnormal signs and noticed she had, what looks like dirt, on a little stubby thing above her butt. First of all, this is my first batch of chickens. What is that little stub? And is what's around it mites or lice? If so, would the rest of my flock have mites? It was only on that one spot. Her anus was fine and the rest of her soul and feathers were fine. I have checked the rest of my flock and they don't seem to have it, I just see little bits of dirt. My whole backyard is dirt so they dust bathe in it a lot. I am just worried that since she dropped dead that the rest of my flock may have some illness or mites that I cannot see. Should I treat them with something?