This is my first time incubating eggs. I am doing it in my classroom with sixth graders. On Monday (day 20), 4 chicks hatched without problem. I still have 20 eggs in the incubator and nothing has happened. Today is day 22. Are the other eggs a lost cause? Is there a way to tell if they are still viable? I heard that I could float the egg in warm water and see if it moves. Is this an option at this stage of the game? Thanks for your help.