The only way I see veins that early is using a VERY bright, tiny flashlight shining down through the top (fat end) of the egg in a pitch black room. I would not worry at this point about not seeing veins. However, like I said before, I do not believe that egg was fertile (would bet money on it in fact) and if they are from the same source, none of them may be. I would try again at day 7 or 10 and see what you have.