Last night my only good Rosecomb egg started to zip. And I am not ashamed to say I stayed up to watch. Glad I did too, because toward the end I noticed the humidity had dropped and membrane was drying and had glued the chick to the egg. So I had assist. My old styro bator has been good to me for almost 9 years, but it looks like I will be looking for a new incubator.
Still, I am very happy with my hatch! Even if I only got one chick.