Lets look at it realisticly! The egg could not hatch because, even if they swallowed it whole, the egg would be attacked by the digestive juices and the turning action of the stomach and well do I have to go on? Even if it did hatch how would it breathe? After all you are talking about a land animal not a parasite. Even if the snake lived and ate the fecal matter, or muciod plaque or whatever it would still be unable to tolerate the human body tempture!
If it was a real story maybe it was a huge worm that looked like a snake and the person thought it was the snake egg they ate. You can't belive everything you see on TV or read! Have a good day everyone!