I observed quail eggsbeing laid over a seven day period then a couple weeks later all the eggs hatched on the same day how is this possible if they were laid on different days?

Answer 1

The quail hen would not have actually set on the clutch of eggs until she decided she had enough eggs to bother hatching. The embryos would not start growing until the hen quail stayed on the nest for extended periods of time, in fact once she started to brood the eggs she would not leave. Eggs remain "dormant" until the mother bird stays on the nest ensuring they all hatch at the same time.