To biologists, chicken eggs are far more than breakfast; this is a picture of a chicken embryo being fed through fluorescent-labeled blood vessels from the yolk.

For a growing embryo, the biggest concern is nutrients; nutrients are transported through blood vessels sprouting independently from the chick to the yolk. With a fluorescent dye each blood network becomes visible, resulting the picture you see here. The center of the picture is the chick, lacy circle surrounding it, the yolk. At this stage, two networks are already formed and the heart is already up and pumping. The embryo wasn’t harmed in any way by the fluorescent dye – the technique is already used in many fields in medicine.

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