I was just going to post the same question
one of my hens routinely has blood spots in her eggs, but now one of my ducks did too,and she never has before... but she also just started laying again after a month or two break...
I am trying to find the thread...but I seem to remember reading something about certain illnesses(at curtial development stages in the hen) can cause funky things with eggs- like mis-shapen eggs, and blood spots.... but now I can not search engine that thread out
I love to share my extra eggs with friends, but I always feel embarrassed explaining blood spots, they don't bother me, I just pick them out- but I worry folks will think I have given them a developing chick or something- so I try to explain what they really are- but it does not seem any less icky when gifting eggs LOL