I'm SW of Lake City, likewise they have never bothered my chickens, though they have caused them to alert and scatter on occasion. We mostly have the turkey vultures. Nothing creepier than a dead snag tree full of them resting on a foggy morning. I know that the black vultures tend to follow the turkey vultures to find food since they don't have the sense of smell that the turkey vultures do, they use sight instead. In some places the black ones have become a problem for new calves and other small livestock. They won't carry them off, just eat them in place. I've heard that hanging a dead one will discourage others from coming (not sure where you would get a dead one, but something that appears to be one might work). Also some say that large dogs are a deterrent, which I do have.