Besides allowing our chickens to produce quality eggs by living outside, eating grass and certified non-GMO poultry ration, we sort, clean, and candle the eggs.
Sorting is what we do after gathering the eggs and during cleaning. Any eggs that have obvious cracks, have a strange shape, really thin shells, are too small, too large to fit in a carton, too stained, or too dirty are set aside. These eggs can be composted but are most often than not, hard boiled and fed to the guardian dogs who we keep around as a check on ground and air predators. Eggs are gathered twice a day, at a minimum, and are refrigerated
Cleaning, the eggs are cleaned with an organic (OMRI approved) egg wash. Though the eggs are laid in nest boxes that are cleaned and re bedded frequently the eggs are still cleaned. The hens jumping into the laying boxes bring dirt in on their feet, and sometimes a clutch will be covered in the contents of a broken egg. Other times the nest box material will get wet and stain an egg shell, small stains from nesting material can be green or yellow due to the chlorophyll in the hay.
Candling is checking the interior quality of the eggs by shining a very bright light behind the egg. This will show you hair line cracks that are too small to notice while gathering, sorting, or during cleaning. Eggs with cracks are composted or fed to the dogs. (Our dogs are spoiled, unsellable eggs are boiled and fed to the dogs.) There are other defects called "meat" and "blood" spots. These are both naturally occurring defects in eggs that do not make them inedible, but certainly does not look appetizing.
Just to be clear, they are NOT developing chicks. For development to begin, eggs must be incubated at 87 degrees for several days. Which is why we check for eggs twice a day, during the morning and evening feedings, and store them well below 60 degrees Fahrenheit.
Example of Candling: This egg has a hairline crack, indicated by the bright line. The candling light is on the right side of the egg.
Yolk color is influenced by the diet of the hen. Greens give the yolks a rich, golden color. Notice that the whites of our chicken eggs even take on a yellow color.