I can't remember which thread I was reading the other day. Someone posted about an egg like that. They cracked it open and found a yolk and white, PLUS another ENTIRE egg, shell and all! I wonder if you have something like that? Your poor hen!!
We cracked it open but it only had 1 yolk, a massive yolk though, and it was a broken yolk not whole. I feel sorry for Jenny, I wonder if her vent is sore?!