Please do not make comments that are unsupported by facts.
Blood inside the egg is caused by a small rupture in a blood vessel as the egg is being processed through the oviduct. You may also occasionally see a small fleshy spot. These are normal and not dangerous, but if you find it distasteful you can discard or feed the (cooked) eggs back to your hens.
Yes, that comment about a scared hen is just bogus.
When you say bloody, how bloody do you mean? A red spot on the yolk was probably caused by a broken blood vessel while the egg is being formed, and the egg can be safely eaten. A red spot in the white, or a "meat spot" was caused by sloughing off of some reproductive tissue--kinda gross, but totally safe to eat.
Now I have had one egg that was BLOODY-bloody and it was my own fault--I'd found an egg hidden in the shavings below the nest boxes, and assumed it was freshly laid. Apparently not, since the embryo had started to develop. This was during the 100+ degree days of summer. EWWWW