With the hatch that I have going on now, we heard peeping the night before last for the 1st time (day 19). We noticed that 2 eggs had pipped before work yesterday and came home to one hatched chick (day 20). The other that had pipped hatched yesterday evening and a 3rd one hatched this morning (day 20 for that one because they were staggered by 1 day). I don't know if it's always within the same time range, but maybe that will give you some idea. Sometimes I don't hear a single peep out of them until they hatch, though, so don't give up. Today is day 21 for the ones we have left and they are very quiet so far, but I still think some will hatch.