Found an old can light in the garage. I bought a flourescent bulb for it, since they don't make much heat.
Cut a hole in cardboard so the eggs would set slightly in it. I made two of these, one for the smaller bantam eggs.
Here it is with an egg on it.
Here it is with an egg on it -- lit up!
How to candle
To candle, darken the room. Eggs can be out of the incubator (or away from a broody hen) for up to 20-30 minutes before starting to cool down inside, so don't rush. You can GENTLY roll the egg on the candler to get the best view.
Out of the 14 eggs in this batch, we removed nine by day 14 that were obviously not developing. There is a chance that a non-developing egg will explode in the 'bator, and that is messy and STINKY. It hasn't happened to me yet, though.
I wouldn't candle after day 16 or 17. The eggs are mostly chick (black mass) and air sac by then anyway, and they should be left alone for the last few days before hatching (no turning from day 18-hatch).
Pics from day 8 candling
(click any pic to see a larger version)
Nice air sac developing,
a good sign
Watch this one hatch
You may want to visit our homemade incubators section or ask questions about incubating your eggs in our Incubating & Hatching Eggs Forum Section.
Also see here for more candling pics: Candling Pics Progression Through Incubation Of Chicken Eggs