Bob, my explanation may not be accurate. Now I’m reading they preferentially deposit the pigment into yolk instead of tissue vs. pulling it from tissue. I haven’t found a great article yet, but here’s something:They pull pigment from their tissues for the yolks, I believe. So earlobes are white when laying and yellow when not. That was definitely the case for Margo and seems to be for Dorothy and Flash, as well.
https://ucanr.edu/sites/poultry/files/186896.pdf