Chicks dying under momma hen yolk not absorbed?

[Naolove]

Hey guys so my clutch under my momma hen started hatching this morning. So far there has been 5 hatched all with the yolks not absorbed and died within an hour or two of getting out. She has hatched out 4 other clutches with no problems so I'm just confused. Anyone else had this from under a hen? I've seen threads from incubators with this issue but couldn't find anything with a hen. Any ideas would be helpful!

 

[Naolove]

Just to add its a huge yolk sack. Not just a small bit, I would say nickel sized?