Flash lights work, put not nearly as well as a proper egg candling light, I always recommend anyone who is serious about wanting to hatch eggs, go to Strombergs or Mcmurray, or any of your choice and buy a $15-$20 egg candler.
They are shaped and fit for eggs to sit perfectly on the end of them, no box, or anything needed, half the time, I dont even turn the lights off (but it does help) they are also about the only way to see into the dark shelled eggs mentioned earlier. With these, you will easily be able to see what looks like a little red spider right in the center of the egg on day 3-5. By day 10, these no doubt, veins will be huge, dark chick in center, and you usually can see it kicking around and moving like all babies do. If by this point, you couldnt say, oh look there he is, I'd say they werent any good.
The yolk doesnt grow! It shrinks, the chick grows and consumes it. As for the dark spot in the egg, yep that is the yolk, or later on really dark spot is the chick, live or dead.
As for candling, always place the light on the big end where the air cell is located, it mighty hard to do it from the pointy end.
As for shipped in eggs. A lot of the time the air cell gets damages from the shaking it goes threw in shipping, and gets a lot of sellers accused of selling infertile eggs.
With some practice, you will easily be able to tell if this is the case on your shipped eggs.
We always candle right when we get them in, if its rupture, toss it, they never hatch, period. Now loose ones will.
Here's how to tell the difference.
Candle from the big end where the air cell is.
On a good egg with a good light, you'll see the aircell membrane line about quarter sized. Try one of your personal eggs or a store bought egg for a reference at first.
Now a loose one, if you gently roll the egg from side to side or end to end, you will be able to see the air cell membrane roll around with you, it's pretty obvious once you get the hang of it, these can still hatch.
Now on a ruptured one, and yes usually there will be some, you wont notice the membrane line on the big end, instead when you roll the egg around as I mentioned above, you will see a air bubble, or multiple tiny bubbles, floating threw the egg, unfortunately, these are junked and can be tossed right then, lots of people still try them, BUT I dare say, it's a lost cause, as that cell it there to help the chick ,by being ruptured, the chick cant survive, you may see a blood ring, or some slight veins at first, but by about day 6-8 , it's all gone.
Hope this helped a little, good luck to all of you!
Aubrey
