Chicks died from hatching?

[ChampionAlex]

Hello yesterday I had three of my eggs start to hatch and they were cracking around ect. I didnt help the chicks in the incubator and now that I have checked all of them have stopped moving and I checked the eggs and none of them were even breeding.. soon after I went to help one of the eggs and the chick was dead. Any suggestions on what I did wrong for these chicks to all die during hatching period? Thanks

 

[chelseajgoss]

What was the humidity at? Its supposed to be 65+ so the membrane doesn't dry out. The membrane turns into practically leather if it starts to dry. not of been enough airflow in there either. The chicks use alot of oxygen trying to hatch, if theres not enough fresh air going on, they cant breathe. Those are my two guesses.