Deb,  
Just curious, what type of incubator are you using?  How much water did you add and how often?  Did your temp remain at 99.5 the whole time?  How far developed are the chicks inside?  How often did you candle them and when you did , did they seem to be doing well at the time?  Did you ever see movement in them?  
  I'm asking these questions to help educate myself with my own batches of eggs.  
I'm so sorry to hear of your loss, I know that is HUGELY disappointing.  Now, you must focus on your new batch on the way and try to think what went wrong with this last batch and when it went wrong.  There is still hope for the new ones,,,don't give up!
Waiting to hear,
Julie