My very first pip early yesterday afternoon had not advanced while 3 others hatched out fine this morning, so I took out the egg (24 hours after pipping), and chipped around where they would naturally zip, and noticed right where he pipped, his little feathers had dried to the white membrane. So I moistened all around the zip area, and noticed that it was helping to loosen the membrane from the feathers, and so I continued with picking off shell, and moistening real well with nice warm water (all the while holding him in a very warm, very wet washcloth, under the brooder light), and when there was nothing left but very moistened membrane, I used tweezers and tore away ever so gently the membrane around him and he finally slid away free. Yolk sac completely absorbed, and chirping like the dickens. My theory is when he first pipped, nothing happened right away, and there hadn't been enough humidity (not in lockdown at that point), and right where he pipped, his feathers dried to the membrane and any time he tried to zip it hurt him, so he was stuck there.....how sad!!! He is doing great now....