In this and the following pages I take you through the different stages of incubating and hatching chicken eggs, from day 1 to hatching at day 21.
We'll go step-by-step, slowly, carefully and with as much practical detail as you can take.
This series is expanded in my free email course and my more detailed Hatching Club course.
In both of those, I guide you in increasing detail through the process.
My email course is free to my Chicken Digest group only. Find more details, and sign up, here.
If this is your first time incubating chicken eggs...
...and if – as I'm sure you do – you take it seriously, you can expect to feel two things: uncertain, and anxious. I certainly felt like that. It's only natural.
You've read all the books, you've seen all the questions on the forums. So much can go wrong at any stage...
But if you can, try to relax and enjoy the whole process.
A mother hen goes through this without too much fuss. We'll use her as our role model as we go through the process.
Of course, things can go wrong. But if you've chosen and stored your fertile eggs wisely, if you're careful and you don't panic, all will be well.
This is what she looked like just a few hours
after she'd hatched.
See the white tip on the end of her beak? That's the 'egg tooth' which chicks use to peck their way out of the egg. She'll lose it within a day or two.
The answer is – quite a lot. It may not seem like it, and you won't be able to see much of the embryo's development, at least initially. But ever since the egg was laid, it has been developing.
It will have stalled once the hen was no longer warming it. But make no mistake: if you have a fertile egg, development has already started before the egg goes into the incubator. Incubation kick-starts the process again.
By the end of this first week, your chick is one third of the way to full development.
The shell of the egg doesn't change at all on the outside until the chick is ready to hatch much later in the process. At that point, she will start to peck through. This is known as "pipping".
Until then, if you want to see anything you'll need to invest in a candler. A candler can be either home made or shop bought. Both are good as long as the light is very bright, and focused.
There's really not much to see at this point. Initially the egg will look clear, apart from the air cell which you may be able see at the 'fat' end of the egg – but probably not before day 4 or 5.
As time goes by you'll notice this air sack become larger. It's here that the chick will eventually hatch.
In these early days, you'll probably be able to see the yolk as a darker "shadow" inside the egg. When I first saw this, I was hugely excited: I thought it was the embryo.
That's how much I knew!
If you're fortunate enough to have light-shelled eggs, from about day 5 you'll start to see tiny spider like markings appearing in the yolk area when you candle your eggs.
In a dark-coloured egg like the Marans or Welsummer, they're much more difficult to spot.
This is the start of the embryo's visible development. The 'spider legs' you can see are blood vessels. They will become much more well-defined over the next several days.
The next few days see the development of the blood supply to the developing embryo, and the eye becomes far more prominent.
If you look closely, you can see the outline of the embryo developing. It looks like a darkish ring around the eye.
Also notice at the bottom of this picture that the air cell has started to get a little larger. This too will become more obvious with time.
In a lot of ways, the first week is the worst. Once it's over and you know the chick has started to develop, you can see your chick developing. You'll also be able to tell whether you have eggs which are infertile and not going to develop.
Next week, we'll watch as the chick develops even more, make sure we're keeping the right conditions in the incubator, and learn what to do with eggs that are just not developing.