IF an egg has dropped into the abdomen, there is no hope if she can't get to a vet. I have done crop surgeries, but never would attempt a major surgery such as cutting into the abdomen without anesthesia. That is never something I would suggest a backyard flock person should ever do!
I lost a hen who had a huge egg-within-an-egg that was way too large to pass and ended up in her abdominal cavity. Poor thing. It wasn't pretty when we euthanized her, realizing what was going on, and then opened her up. No way to save her.