An Egg Candler is used to see the inside of a fertilized egg during incubation. This device consists of a bright light, and only one hole, the size of your egg for the light to escape through. The egg is held in front of the hole or placed on top of the hole and the light is turned on. This allows you to see inside the egg. For example, you can see on day 7 of incubation whether or not the embryo inside is developing into a chick.
Step 1: Parts
To make an egg candler you will need:
A tube just big enough for the egg to sit on top of it and for you to hold it and the egg. You can use toliet paper tubes or paper towel tubes for bigger eggs.
A light big enough to fit in the tube and bright enough to shine through the egg.
If your tube leaks light use black tape (electrical tape) to seal up the holes. You don't want a light that is too big because then you will have to use a lot of electrical tape to seal the leaks.
I am currently hatching 4 Bob White Quail eggs which are small eggs and that is why my candler is so small.
Step 2: How to put it together
The light goes inside the tube and the electrical tape is to seal major light leaks. For bigger candlers leave the power switch exposed so you can turn it off and not have to take apart your candler.
Step 3: Candle
You can usually candle your egg around day 3 if white or day 5 or 6 if brown. Go to a darkened room. Turn on your candler, take out an egg, and put it on the opening where the light comes out of. If it's a good egg you should see the veins, air sack, and possibly the embryo on the inside of the egg. You can candle your eggs every few days.