Okay, candling as it was described to me by my elders and how I've always done it. You're going to want to put the light on the rounded end ( this is where you will find the air cell, gets you a better view into the egg. )
First 7 days of development inside an egg ( my experience )
- You will see blood VEINS, not blood rings. Heart beat is noticeable from day 3, if I remember correctly.
- Small blobs visible near the heartbeat are the chicks.
- Clear eggs or eggs with lots of clearer looking spots ( porous ) should be tossed at this time.
- Eggs with blood rings should be tossed at this time. A blood RING is exactly what it sounds like. It's a ring of blood formed around the egg and is obviously blood.
- Air cell will still seem small. "Uneven" air cells can be tossed at this stage, but may or may not hatch now. Pictured is a 'regular' air cell development guide.
- It's best to measure your air cells, maybe even mark them with a pencil. Check that they are growing properly. An air cell that isn't growing/developing is probably a dud.
This is how a chick develops. Give you an idea on what amount of space you should be seeing for what stages of growth.
This egg appears to be between 10 and 12 days to me. Possibly less, but in that area.
As you can see, by day 10 it would be obvious if you had any quitters. You can also probably use this chart to find out what days of development your eggs are at, and find any quitters / bad air cells.
By day 10, chicks are very obvious. Clear eggs should be tossed at this point as they may explode. If no sign of development, toss it. If you're second guessing, let it sit. Use your nose.
You can also 'float' eggs to determine if they're good or not. A bad egg will float. A good egg will produce air bubbles if a live chick is inside. Try not to float often as it can be ( as I am told ) harmful to the embryo.
Generally, fresh eggs will lie on the bottom of the bowl of water. Eggs that tilt so that the large end is up are older, and eggs that float are rotten.
As far as hatching eggs go? - I just don't recommend it. I don't float them. But supposably viable eggs will produce bubbles.
Does any of this help? I know I'm all over the place here.
THIS WAS A GREAT POST FOR EVEN ME TO READ! THANK YOU!