I'm not sure. It could be the membrane came out, or possibly a type of lash material. Can you put on rubber gloves and inspect it? Lash would be solid. If it's membrane, it would be thin and slippery.
Thank you! Chicken is around 3 years old. Not sure if solid. I didn't have gloves on at the time and when I took the picture flies were attracted to it. Looked wet! She did go around two weeks without laying so thought possibly egg bound. Gave her warm baths etc. This is her first attempt at an egg since the dry spell!