A blood ring is caused when the develping embryo has made enough blood vessels that when it dies the ring appears. Embryos can die earlier and later, and give a different appearence to the blood ring, or no apparent blood ring if it dies much later.Thanks.. Can improper humidity cause this...
Many causes of death to an embryo, but humidity itself is not one I would think of.
Lack of ventilation
dropped or rough handling
spike in heat or quick change in temp
I'm sure other things also play a part, but these are the most likely IMO.
It happens occassionally to me too, probably to all of us. As I learned how to handle the eggs with slow methodical handling, no dropping or bumping, and slow turning, I have fewer blood rings. But like I said it happens.
How are the other eggs doing??