What on earth is wrong with this egg

[Farm life101]

Hello all,
I am hatching 2 bantam silkie eggs and 2 duck eggs in an incubator and I noticed this egg looks odd. It’s been in the incubator for 15 days at a steady temp of 99.5 (Fahrenheit) and a constant 55% humidity. All the other eggs are growing fine and this one was fine about 4 days ago so what happened?

 

[Shadowfire]

The egg appears to have a blood ring, a clear indicator that the embryo has died.

 

[oldhenlikesdogs]

Eggs are porous. My guess is it's some bacteria inside the egg growing. I would get rid of it.

 

[Farm life101]

Okay thanks