What is this in my duck’s egg?

[hugitnotnugget]

I cracked the egg and found this? Isnit an embryo? She wasn’t laying on it I don’t think but it may have been under their heat light. But it has been very cold here lastley. 25 degrees F.

 

[sourland]

It appears to be a 'meat spot' - sloughed off tissue from the reproductive tract.