I've read through these threads....didn't quite get answers I needed. I seem to have a number of hens whose yolks on their eggs are very soft. In other words, when they are cracked for fried eggs, the yolks all break. Along with that, I am getting a number of softer shells....when I go to collect, they crumble in my hand. My girls are going on three years, have free feed on oyster shell, Flock Raiser and they are free range during the day. Any thoughts? Thank you.