When trying to hatch eggs such as chicken eggs either out of an incubator or by means of natural process, the best thing to do is intervene every so many days to check in on eggs to make sure they are either going to hatch or they are going to go bad.
How to tell if an egg is fertile?
A fertile egg will have small spider like veins when candled through with a flashlight or strong lighting source.
What is candling?
Candling is a method of seeing exactly what is going on inside an egg without actually waiting until the egg hatches. To candle an egg, the egg needs to be lifted up from its place in the incubator. You need to hold the furthermost ends of the egg, only this way can light travel into the egg and back out the other side. You can do this by holding an egg between your forefingers and thumb very carefully.
When you shine your light through the egg, you are checking for any signs of activity such as blood veins, dark masses, and small swooshing objects. This can be used with any kind of flashlight, or just holding an egg very close to a light bulb, light, lamp, or any other source of light.
What will define a bad egg?
When looking for an egg that is fertile, the first thing you need to know is how to identify an un-fertile egg. Also known as a bad egg, or a dud in some trades.
Candling a bad egg
When candling a bad egg you will see nothing inside, sometimes you may see something but it may not be in motion, another good clue would be if you have had the egg for a long period of time. A week or more and there has been no significant changes within the actual egg is a bad sign.
How to identify a bad egg without the candling technique?
When looking for bad eggs, it is also faintly obvious without a light source tactic to tell if an egg is bad, this method would be known as the sniff test.
The sniff test is when you smell your eggs; any egg which may have a rotten egg smell is definitely a bad egg and needs to be removed from the fertile eggs right away.
How to tell if an egg is about to hatch?
When an egg reaches a specific point where others are hatching, or you would just like to know when you should be more alert for emerging of babies, there are a few tricks to getting a hint as to how far the chick within the egg has developed.
Through candling if a chick is close to hatching you will see little to no light able to go through the egg as before. Instead, it will be like trying to shine a light through a rock. It won’t work.
The other way to tell if an egg is getting near hatching point is if just recently the chick within the egg was moving around a lot, and is now barely moving, this is due to the fact that right before a chick starts hatching from an egg the chick will become quite still due to the lack of space within the egg. This lack of space is vital in enabling a chick to easily push its way out of an egg.