I'm having the same issue. I have lost 3 on their own, and I have another one who is fighting to hold on. Someone suggested to me that it is Omphalitis so I am treating the 4th with antibiotics and treating his umbilicus with Bactine. If you have more hatch that way, try it. If it doesnt work, then at least they can have the chance to go on their own or wait and see. They may pull through it.