In both my chicken hatches I candled and listened before lockdown and I could hear tapping (like they were tapping on inner lining) but no peeping. One also looked to be threw lining already and I could hear peeping in that one and that was the one I saw wobbling first. (When they break threw lining you can see their shadow above the airspace) I don't think they peep until they break threw the inner lining and breath air. But I'm not positive. Also when my daughter peeped at them you could hear them peep back and wobble more once they had pips. Mine were not due til friday but hatched today and my last ones were 2 days early but I have read they can be later than their hatch date.