Bigandlittles
Songster
I’m no expert and have never experienced this but I did find a good article that might help you.
https://crittercleanout.com/chick-hatched-with-yolk-sac-attached/
Hope this helps. Keep us posted.
https://crittercleanout.com/chick-hatched-with-yolk-sac-attached/
Hope this helps. Keep us posted.