Candling Eggs????

[zaharadesert]

Hey y'all. I've just candled my eggs after 7 days, and one of them seems to have a dark, very distinguished vein running all the way around lengthwise. Is this an internal crack or something? Is it bacteria???

 

[brahmabreeder]

Is it just one vein that kind of makes a ring in the egg? If so it quit part way through incubation.