My first set of chicks to hatch caught me by surprise and they were out of the egg before I knew it! I have a hen who has been setting on four eggs and I saw the first pip this morning! I hustled to action!!! I have moved the eggs into a safe place with a heating lamp (she had already killed one egg a few days ago). Now, like you I have my lawn chair and camera in hand. I'm glad to know a time frame and hate to miss the hatchings again!
My other chick family is doing great and they had a wonderful mama. In fact, they are due to move to the "adult coop". Just in time for the new little ones!!