Should I be concerned that my hen laid an egg with blood on the shell?
When a hen has just begin laying, there can occasionally be a little blood on the egg shell, but it is usually no cause for concern. Eventually her vent gets used to stretching when she lays, and becomes very elastic. However, at first it does occasionally happen that with a large egg she might bleed just a little. And it can happen, too, to an older hen if she lays an egg larger than she is used to.
If there is a lot of blood, if there is blood every single day, or if you see blood on your hen's vent (her rear end), then you will want to be concerned, and should contact a veterinarian. However, just a little on the egg shell... well, the poor hen. Ouch! When it is infrequent and small in amount, it is not cause for alarm, don't worry.