Yikes. Poor chicken, that couldn't have been comfortable. I wonder if she has salpingitis? It's an inflammation of the oviduct and can cause hens to lay "lash eggs" which look kind of like that, only usually more egg shaped. Texturally looks very similar though. Some more info
here
Does she have any other symptoms? Hopefully she gets back to feeling better.
“Action on behalf of life transforms. Because the relationship between self and the world is reciprocal, it is not a question of first getting enlightened or saved and then acting. As we work to heal the earth, the earth heals us.” ~ Robin Wall Kimmerer