I did a lot of research before deciding to get chickens(off and on for a year now). I got them home today. I have them in a brooder i.e. a tote with paper towels down and then a metal mesh on top of that for traction. For heat i am using a red heat light and thermometer. For feed I am using a mason jar feeder and waterier. I am using medicated chick starter and granite. As I took each chick out of the box I checked their vent and then dipped their beak in water. One chicken had a clump of black stuff about an centimeter down but vent area was clean and dry. What is this should I be concerned should I try to remove it. I did try wiping it off but its on there good and I thought that that might be where the egg sack was attached. Please help I am very new to this.