When do chicks absorb the blood from the membrane

[Chicken Boy1234]

On what day do chicks absorb the blood from the vessels?
Thanks

 

[sumi]

When the chick starts hatching. Once the chick begins to hatch and is breathing, it does not need the vessels to supply it with oxygen any more.

 

[Chicken Boy1234]

Ok, thanks!!

 

[JessElizabeth]

On what day do chicks absorb the blood from the vessels? 
Thanks

The chick has hatched and is showing signs of life. It flaps around and all but it has like a big sack of blood behind it. What do I do? Will it be okay?