Monitor the ones pipped at the wrong end and listen. After approx. 24 hrs. if they sound like they are getting tired/weaking of the cheeping and no further zipping, then you can help them - if you so choose.
I had one at the small end and waited. She was doing pretty good but unknown to me, she was growing faster and unable to turn to zip that shell. After several hours she started to sound weak, thats when I said 'it was time" and I went to work to get her out.
I think it was about 16 hrs. or more before I started getting her out. Although to me it seemed like days at that time.
Today she is a great layer and very healthy young lady.
Well, after spending an absolutely wonderful afternoon at Miss_Jayne's house, I came home to lots of action in the incubator. The moment I began "talking to the eggs", those chicks started peeping and busting through the shells like gang busters! 1 hatched within 15 minutes of me being home, another is almost out now, and 9 others are pipped. For the ones who had not made any further progress since this morning, I did open their pip hole a little more...hopefully that will speed them along. Stay tuned...this is gonna be a loooooooong night!