yes i am aware of that this is different and is a direct path inside the egg as if that small spot is misformed.its not a simple calcium deposit on the outside of the shell.
One of my Lohman browns laid a nice hard thick egg thismorning with two small clustery growths on the shell when i scratched at it it crumbled away and a tiny hole leaked out some white. ive never seen it before? the egg was fertile.