Sounds like you might be cooking too long? I dont know. How do you cook them?
I put my eggs in to where the water just covers the top of the eggs, bring it to a boil on a med-hi temp. As soon as it gets a good boil going, then turn off the heat and let them sit on the burner for 10-12 minutes. At that time I run them under cold water in the pot and let them sit in cold water for about 15 minutes. Come out of the shells great and theyre more of a soft boiled egg, where the yolk isnt as dry and chalky. Love em that way.