I have a friend who would like some of my eggs to incubate. Thing is, we have confirmed mareks in my flock. I know the disease isn't transmitted inside the egg, but wouldn't it naturally be present on the outside of the shells? I'm wondering if there is a way to safely clean my eggs before giving them to my friend, or is it too much of a risk of passing this disease on to her chickens.... Any advice is always appreciated... Thanks an advance!