1. EGG
AIR CELL
THE
OF THE
Author:FabioBittencourt
BroilerandturkeyincubationSpecialist
This phenomenon, when properly
understood, is very relevant for anyone
who wants to improve the productivity
of their hatchery.
The content of this article aims to
produce insights for the reader so that
we can help you at some point:
Or by the strategy of defining egg
handling routines, from broiler
breeder farms to the hatchery,
Or by improving the embryo
diagnosis, remembering that it
starts with observing the air cell.
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aviNews International June 2022 | The air cell of the egg
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2. E
G
G
S
H
ELL AND MEMBRANE
S
The size of the air cell varies
according to:
The permeability of the shell,
the age of the egg, and the
temperature and humidity
conditions to which the egg is
subjected.
The size of the air chamber
is also related to the size of
the egg. The larger the size
of the egg, the larger the air
chamber.
The air cell is located between the inner
and outer shell membranes, which remain
in contact with the albumen and the shell,
respectively.
Its shape resembles a double convex lens.
The curvature of its outer boundary
is the same as that of the shell. The
opposite side may be less convex if the
air cell is small. But it resembles the
curvature of the outer boundary if the
air cell is large.
The air cell is
sometimes called
the air space or air
chamber.
PROPERLY
DEFINED FEATURES
Cuticle
Eggshell
Innermembrane
Outermembrane
Chalazae
Yolk
Blastodisc
Albumen
Aircell
When the egg is laid, it
does not contain an air cell.
The membranes and the eggshell
are taking up the space.
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aviNews International June 2022 | The air cell of the egg
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3. How quickly the air cell form
depends on how the egg is
cooled after being laid.
If the air temperature is low,
the air cell may appear within
a short time, such as two
minutes.
In a hot and humid
environment, it may
take several hours
to form.
Immediately after emergence, its average
diameter is 0.5 to 0.9 cm, and the volume
is 0.1 to 0.2 cc, depending on the size of
the egg. But after two hours, it will be
1.3 to 1.5 cm in diameter.
Therefore, the initial size of the air cell
represents the reduction in the volume of
the eggs.
It is worth noting why it is not
recommended to incubate the egg
during the day or even before lowering
the internal temperature. The formation
of the air chamber does not depend on
chalazae or the yolk.
There is considerable evidence
supporting the previous explanation of
the origin of the air cell. For example, the
refrigerated egg has its air chamber
enlarged. The opposite is also true, it
becomes smaller when the egg is
kept warm.
In most chicken eggs,
they appear in 6 to 10
minutes.
Since the egg begins to lose
heat immediately after it is laid
and continues until its internal
temperature approaches that of
the air around it.
2min
6
10
a
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aviNews International June 2022 | The air cell of the egg
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4. The normal position of the air cell
is at the farthest angle of the egg
(Figures1and2) and its functions are:
Perform gas exchange.
Provide air to the embryo to pip the
inner membrane, the moment when
pulmonary respiration begins.
The embryo head rests directly under the
air cell, a reference measurement position
for the external height of the internal and
external pipping.
The inadequate size and position of the
air cell will make it difficult for the chick
to pip the eggshell properly. InFigure3
the typical section is observed, while in
Figure4 the section is abnormal, which
will lead to a lesion at the crest
insertion level.
If the air cell is not at the wider
end of the egg, the chick can
suffocate inside the shell.
Figure1. Theaircellshouldwidentoreachthewidest
diameteroftheegg.
Figure3. Normaleggshell.
Figure4. Normaleggshell
When you notice these lesions on the
beak (Figure5) it is a sign that this chick
spent a lot of energy to get out of the
eggshell, much above what is considered
normal. This extra effort will directly
impact the quality of the chick
(example: less livability).
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aviNews International June 2022 | The air cell of the egg
5. In fresh eggs, the air cell is rarely
displaced from its normal position at the
egg’s larger end.
Sometimes, the air cell appears to be
within the egg’s inner membrane, and
it moves freely around the albumen
throughout the egg. This is known in
artificial incubation as a mobile air cell.
However, sometimes the
air cell can be found at the
narrower end, or on one side,
of the egg.
Usually, but not consistently, eggshell
pores are more numerous at the egg’s
larger end than at the smaller. So this
gives us a reasonable basis for setting
up our egg collection program because
when the egg is laid, the part of the air
cell comes out of the cloaca first.
After its formation, the air cell increases
in size and causes the evaporation of
humidity from the egg contents. For this
reason, air cell size is often taken as an
index of egg quality and age.
In this way, the wide part where the
air cell will form will come in contact
with nest or bedding materials.
And as we’ve already talked about
how the air chamber is formed, it’s
evident that eggs with dirt on the
wider end are more likely to be
contaminated.
These chicks should be
housed as soon as possible
and, preferably, they are not
subjected to long trips,
as this will worsen their quality.
When this is perceived, it is
recommended to reduce this negative
impact to avoid the holding time of
these chicks longer than five hours
after hatching.
Figure5. Chickwithbeaklesion.
POROSITY
INADEQUATE POSITION OF
THE AIR CELL
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aviNews International June 2022 | The air cell of the egg
6. Theaircelloftheegg
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Rough handling, particularly in
transport, can damage the eggshell
and the architectural distribution of
the egg’s contents and thus accelerate
physical disintegration.
The dissonance can cause separation
between the shell membrane and the
egg membrane, resulting in a somewhat
mobile or unstable air cell. Sometimes
a loose air chamber consists of several
air bubbles forming when the inner
membrane ruptures.
This fact is observed in a widespread
way in hatcheries, which causes
significant damage. When we have
many eggs with such characteristics,
we have great possibilities of
increasing the contamination of eggs
by the so-called microcracks.
One way to solve this doubt is to
separate these eggs when found, cook
them in water and open them after
they are cold. Then we will be able to
see where exactly the air cell is.
In double yolk eggs, the air
cell is almost always shifted
to the side of the egg.
Eggs with air cells of this type are not
appropriate for prolonged storage.
It can result in a relaxation of the
albuminous structure, including
chalazae, whose function is to keep
the yolk in its central position for the
proper development of the egg embryo.
ROUGH HANDLING OF EGGS
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aviNews International June 2022 | The air cell of the egg
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