How many days late are they? What day is it for them? I have heard some hatch at day 27 or 28! Dont give up, unless you can no longer see blood veins, or movement. If there are blood veins, they are still alive. When the chick dies in the egg, the blood veins will dissapear, and all will turn black. Make sure when you candle them....you hold the light where the air sack is. The large end. Be patient...there might still be hope!