It is just an extra layer of pigment from my understanding. You can rub the brown off of most eggs if yiu scrub hard enough. What breed of chicken layed it? Speckles are normal/common for some breeds.Are they blood? Poop? They wipe off with a firm scrub and end up looking like all the other eggs. Curious about why one hen has them but the other four don’t?
Looks like it is part of the pigment or bloom.
It's completely normal, and not a problem. Not blood or poo. Just an extra layer that the hen puts on the egg before it comes out so that bacteria doesn't enter the egg.
Speckled eggs are always fun to have, and look beautiful in the egg basket