Checking eggs for fertility...cracked one open and found something weird looking

[Cierrascoop]

Blood spots are from a blood vessel breaking when ova is released from follicle.
Meat spots are from a tiny piece of tissue breaking loose from the reproductive tract.

Can happen to any age layer.
Some birds can be more susceptible to them and have them always.

I do feel like my RIR has them a lot now that this has been mentioned. It's really good to know. I didn't think much of it.