I just had one chick hatch two days ago. Had to go get a couple of bantam chicks to keep it company. Single chicks do not do well. They set and cry constantly. now with three chicks I very seldom hear an noise out of them at all. I am not sure what to say about late hatch other than to low of a temp. Do you have any pips at all? And have you been opening the incubator since day 19? Just FYI. most embryos fail in the first three days or the last three. for me these are the two periods of time that it is most critical to have conditions at there best. Fingers are crossed for you. Sorry I can't offer much more than that though.