I’ll give you a strange find. Working in a Chicken hatchery laying house we often saw strange things. Lots of double yoke eggs, they were often bigger than the regular eggs.
Strangest was a huge egg! When we cracked it open we found the albumen inside and a complete regular sized egg. An egg in it’s shell inside a bigger egg.
Haven’t seen that since. That was sixty years ago.
That poor hen…….ouch!