Incubation - Day 16.

What's going on in the egg today?

We're just five days away from hatching now, and our chick is growing fast. There's very little room in the egg and what there is, is taken up almost completely by the chick and its yolk.

If we opened the egg at this point in incubation we'd see the chick now covered in down - although not the fluff we see in pictures : it won't look like that until several hours after hatching.

What's happening to the chick?

Carrying on from yesterday the chick's intestines continue to be drawn into its body and the yolk is now becoming more important in terms of providing nutrients throughout the rest of incubation, as the albumen (the white) of the egg is almost gone.

The incubated egg at day 16.

The incubated chicken egg at day 16 - an artist's impression.

The bony structures continue to harden as the chorioallantoic membrane carries calcium from the shell to the chick, and as the chick loses moisture through the shell it's replaced by air so that the air cell, at the blunt end of the egg, is now growing quite large.

And finally today, some chicks (but by no means all) begin slowly to turn their position in the egg so that they move towards the best place for hatching, which is the head towards the blunt end. It's here the beak will 'pip' through into the membrane and then through the shell.

What can we see if we candle the egg at this stage of incubation?

The chick is now filling so much of the egg that it's almost as easy to see inside by candling in a room with a light on, which is how the picture below was taken.

A chicken egg candled 16 days into incubation.

The embryo is the dark area covering progressively more area; the blood vessels are clearly visible underneath and the air cell is much bigger than it has been previously. 

Below is a photograph in a darkened room; it's possible to see more or less exactly the same features here.

A chicken egg candled in a darkened room, 16 days into incubation.

If candling today, you may be able to see movement in the lower area as the chick begins to prepare its position for hatch - but don't worry if you candle now and can't see it. 

From now on, the growth of the darkened area and of the air cell is the best indicator that the chick is still growing.

What should we be doing today?


We will be candling the eggs again immediately before 'lockdown' at Day 18. There's no point disturbing them before that.

Make sure your ventilation in the incubator is good to prevent the humidity levels rising too soon.  If you're incubating in the Brinsea Mini Advance (or any other of Brinsea's small incubators) it's taken care of for you.  In the larger Octagon 20 you need to make sure that the slider on the front of the incubator is at the midway point.

The only other issues for today are the usual temperature, humidity and turning reminders.

Day 16 of incubation to do list.

Question of the day.

The humidity in my Brinsea Octagon 20 is too high - how can I reduce it?

On the front of this incubator is a slider which will open the vent, allowing more air into the incubator.  This also reduces humidity at the same time.

I've found I need to experiment with this in different hatches.  Begin by opening it and watching the digital readout on the lid.  If it falls too low, close the vent a little and wait for it to stabilise before altering it again, if necessary.

My Brinsea Octagon 20 with vent and slider indicated.

Chick of the day!

Here's one of my lovely Light Sussex chicks, just three days after incubation ended. 

This is what it's all about - hatching lovely, healthy, happy chickens!

A Light Sussex chicken at 3 days old.

Other popular pages.

Incubating? Here's all your questions answered!
Choosing an egg incubator - link.
Red star chickens - a breed profile.

Would you like a reminder e-mail at each step of the incubation process?

Join us - It's just 28 days to Perfect Peeps!

Have you joined my incubating and hatching group yet?

If you're having a go at hatching your own eggs and it's new to you, you might want to consider joining my free 28-step series called "Hatching Happy Chickens".

You'll have e-mails personally delivered every day describing that day's developments in the incubation process, and pointing out as this page does exactly what you need to be doing.

It's free, and it's fun!  Don't miss out - click on the pic to have a look at more information about exactly what you'll get.

Looking forward, looking back!

The easiest way to follow my incubation 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.




Link to my 28 day guide to incubating and hatching chicken eggs.
Go back a step to incubation, day 15.
Here's a link to day 17 of my incubation 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.

If you wish to use these or any other images on this site for educational purposes you are required to contact me by using the form to be found on this page

For my full copyright policy see this page.

Link to Raising Happy Chickens home page.