I just got some eggs in the mail. As I was placing them into the incubator, I candled to see how bad the aic sacs were. To my surprise, two of the eggs had blood rings! They had only been shipped three days before, but when I cracked open the eggs, there were definate blood rings along with what appeared to a 3 to 4 day old embryos. How can this happen? Could this be because of the heat during shipment? Why did only 2 of the 15 have it?