It is not the same in every case just most: you will get zero chicks, and if you get two chicks, they are more than likely going to be deformed. Sometimes one normal one comes out and the other is dead.
Have a look on youtube - there's a video on there of healthy twin chicks being helped to hatch out of one egg. Think that's the very unusual exception though and like Debi says they almost always die or are deformed...
