Mine dont eat greens.... What other foods are high in calcium? Here's what's reacts they have had this week:
Corn (a favorite)
Mealworms
Cantaloupe
Watermelon
Corn bread
A medley of cheese, rice, and broccoli
Cucumber
Papaya
Banana
It is only my EE. My Silkie laid the funky egg, but my Orpington's eggs are fine...
I don't think any of that is high enough to cause it. I only have one that lays eggs like that also (out of six that have laid). I just thought it was her inner workings, how she did eggs. I never looked into it more, although I thought the same as you.