If your light is not bright enough to see any veins, the dark mass of an embryo has not yet gone beyond the size of the yolk sac was initially. It will be about day 10 where the embryo will reach the aproximate size of the yolk, and where the developing tissues will be casing a significantly darker shadow than that of a yolk. If you had a very bright light, you could probably see more. I would wait till day 10 or 14 to candle again with dark eggs.
By day 11, any movement is likly the whole embryo rotating around. The heart is encapsulated into the chick's body by day 4 or so if I remember right. If you want to see the actual heart beating, crack open a 2-3 day old incunbated egg and you can see blood coursing through the heart which is still on the outside of the chick.
By day 11, any movement is likly the whole embryo rotating around. The heart is encapsulated into the chick's body by day 4 or so if I remember right. If you want to see the actual heart beating, crack open a 2-3 day old incunbated egg and you can see blood coursing through the heart which is still on the outside of the chick.