The blood is normal - the blood vessels that the egg passes by on it's way out are being disturbed and things have not yet had a chance to "toughen up" in there so to speak so it is easy for there to be some bleeding happen for the first bit of a hen's laying life. The mechanics of that last...
X2 - "a few days old" likely means they had been I the store for a few days + 2/3 days old when they arrived at the store=about a week old at purchase on the younger looking, and closer to 10 days+ on the older looking (more feathered out)