J.S.
I learned the other day from a chicken farmer that the eggs are too fresh if the shells are sticking when hard boiled. She said that they peel the best when the eggs are 7 to 10 days old. Also the gray or greenish ring around the yolk is from cooking too long. It won't hurt you or the egg, but the cooking method suggested of boiling the eggs and then turning the burner off and letting the eggs sit in the water for 20 minutes is what she suggested.
Good luck!