That stunned me too! Seen more than my share of lash eggs from the rescued hens I took in a while back as well as from my Marek's survivor so I could identify that right away. The rest looked nothing like any intestinal shed I had ever seen even the nasty ones from the (supposed to be) pullets I got once that turned out to be loaded with worms and cocci. That was why her vet was absolutely "gobstruck" as she put it that the hen hadn't died instantly or at least bled to death. She told me curiosity got the better of another vet that it was shown to and autopsied the whole thing. It definitely was a diseased ovary. Might hear more because they were discussing sending it off to the University of Edinborough for further study.I'm no vet, but I would not expect that to be her ovary.
IF it is, she will take on the secondary sex traits of a rooster (larger comb, wattles, crowing, mounting hens.) Hens only have one ovary and if they lose it, they turn (infertile) male. I had one Production Red do that. I would suspect it is just a clot and sloughed lining, and that if she is not too old, she will lay again.
It is really interesting, keep us posted.
Definitely will pass along anything further I learn.