Its not impossible to hatch out twin babies. Most if the time though they dont make it from what ive heard. Its optional. If you decide to leave it and see what happens, you will need to hell hatch. One baby will be facing the air sac and will be able to breath, the other will be at the other end of the egg with no air. So once the one internally pips, i would try to find where the others beak is, and pull just a tiny amount of the shell away (not poke or stab the shell! Just grind gently wil a butter knife or in a way it wont hurt the chick) that way the second chick can breathe. Its risky to do that though, because of the blood vessels. If you EVER come into contact with blood while helping durring hatch, cover with a warm paper towel and wait a while before helping again. The chick could bleed out even with just a few drops. But that chick breathing is what will be important. As long as they are both breathing, they should be okay in there for a while until your SURE they need more help ( that way you dont risk bleeding, you want them to absorb all that before they come out).
I think i saw a youtube video of it too. Look it up. The one i watched she used a knife, which scared me a little, but it worked for her! I personally think tweezers would be best! STERILE of course!anyways. I hope it helps! If you feel likenyou wont be ablemto help, or if you wont be able to be home when they hatch or anything, dont feel bad just taking it out. **** happens, and its okay to do if its what you feel is best for you and the chicks! I hope this helps! Keep updated!