they're due to hatch any day, i've heard i'm supposed to leave them in the incubator for the first couple of days, do i need to do anything? like lift the lid to exchange some air? i've got a hovabator and a bit reluctant to take the lid off any more than i have to because that seems to upset it in a serious way and it starts going all cold and hot and stresses me out!and what happens if they dont' all hatch at the same time? are they supposed to collapse the day before they hatch?