Fresh-laid eggs are best. They're fine for scrambling, frying, or baking. But here's what I always say when I bring a carton of eggs as a hostess gift: if you're planning to hard-boil them, or whip the whites for a souffle, you need to age them a bit. Leaving them on the counter overnight should do it.
The color of the shell indicates nothing other than the breed of the bird. A pure-white shell may come from a happily pastured hen, and a brown or blue or green one from a hen kept in a cage.
If you break open an egg and the yolk is a shockingly bright orange, congratulations! It means the hen has been out on grass, which has transmitted its gift of carotene to the bird, and now to you.
If you break open an egg and find a slight red spot in the yolk, don't freak. It is NOT an embryo. It just means that a tiny blood vessel ruptured as the egg traveled down the oviduct. It will vanish without a trace in cooking.
According to Temple Grandin, laying hens are the most abused of all farm animals http://www.grandin.com/inc/animals.make.us.human.ch7.html. If you find it in your heart to care about the welfare of chickens, spend an extra few cents and buy eggs from cage-free hens.
Hens are bright, warm-hearted creatures, not mere egg-making machines. Let us try to see beyond the egg on our plate to the living, questing being that laid it.