Candling detects bloody whites, blood spots, or meat spots, and enables observation of germ development. ... Candling is done in a darkened room with the egg held before a light. The light penetrates the egg and makes it possible to observe the inside of the egg.

When should you candle eggs?

Eggs may be candled after 5 days of incubation and every few days thereafter. For best results you should candle eggs in a darkened room or in dimly lit conditions. The candler should be held right against the shell at the larger end of the egg where the air sac is located.

How do you candle an egg?

Like the name suggests, people use to candle eggs using an actual candle. They would place the egg next to a candle flame and inspect the inside of the egg from the light of the flame. Nowadays, you won't need a candle; you need a very bright light that can create a tight seal on the outside of the egg.