We now have only another 24 hours of incubation left before 'lockdown' and four days (on average) to hatch. The embryo of the first two weeks is now definitely a chick and continues to grow in size so that it is almost filling the egg at this point.
If we could open the egg today we'd see the yolk on either side of the chick, some fairly large blood vessels and the chick itself, covered in down but wrapped inside the membrane.
We're coming close to the final stages of incubation.
The incubated egg at day 17.
The chick is almost fully developed and beginning to get itself ready to hatch. The intestines are still being drawn into the stomach and the kidneys are beginning to make urine. You'll be able to see the result of that left behind in the egg once the chick has hatched.
The egg white has been completely absorbed and the chick will start to ingest the yolk between now and hatch day.
Not a lot!
As the embryo fills almost the whole egg now, all we can see is a dark area which is the chick. The slightly lighter area underneath is the yolk and the very light area at the bottom is the growing air cell.
You may be able to see very light-coloured markings on the air cell. This is where I've candled at Days 7, 12 and now 17 and marked the air cell each time. You can see from the arrows how much it's grown in those ten days.
These markings have two purposes. They tell me the chick is still growing, and they tell me more or less where the chick should begin to break through the shell in just a few days' time.
Tomorrow, we will be preparing the incubator for hatching, candling for the final time and adjusting humidity and ventilation levels.
If you'd like to know what you'll need tomorrow when we come to 'lockdown' your incubator, click on this link.
This is simply so you have what we will need at the ready - do not lock your incubator down now unless you're hatching bantam eggs.
What exactly does 'lockdown' mean?
'Lockdown' is simply the last three days before hatching, when the floor of the incubator is slip-proofed, humidity levels are increased and the lid is left closed until the chicks have hatched.
Lockdown for chicken eggs will take place tomorrow; for bantam eggs it can be done today as bantams sometimes hatch a day or two earlier.
This is one of my Golden Laced Wyandotte chicks at just 5 days old. It's worth bearing in mind that as we go through this incubation series, this is what we're aiming for - a healthy, happy little chicken!
Even though she's less than a week old, you can see clearly how her wing feathers are starting to develop. This chick was using them to get out of her brooder before the week was out!
If you want e-mails personally delivered every day of incubation with a link to my pages telling you exactly what's going on during each step of the incubation process, you need to sign up for my series called "Hatching Happy Chickens".
If it sounds interesting to you and you'd like to know more, the image to the left is a link to details about exactly what you'll get.
And the best thing? - It's free (at the moment)!
The easiest way to follow my hatching series is to sign up for the e-mails. However, if you'd rather not do that, these are links you need to work logically through the series.
Important: copyright warning.
'The Incubated Egg' image is a commissioned artist's impression and, like all images on this site, is subject to copyright under the Copyright Law of the United States of America 1976.
Under no circumstances is permission granted to copy or otherwise use this image.
All other images of candling on this and other pages are my own and are not to be used without permission.
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For my full copyright policy see this page.