The red spec has nothing to do with a rooster. It is a burst blood vessel in the eggs that happens regardless of whether it’s been fertilized. Fertilized eggs have a white ring around a white dot. Unfertilized eggs just have a white dot. Both are generally imperceptible unless you’re looking for it
Sorry, I had not read far enough to see this. Don't mind me, I'm up past my bedtime. Thanks for that explanation, @JuliB.