Hatchery Management
Barry H Thorp BVMS PhD DipECPVS MRCVS, St David’s Game Bird Services
are favoured for longer storage. Ideal temperatures
Background
The purpose of a hatchery is the incubation and
hatching of eggs to produce good quality chicks. The
basic requirements are a supply of good quality eggs
that have been correctly stored; and the provision of
the correct temperatures and humidity throughout the
incubation and hatching process within an environment
that is free of pathogenic bacteria, moulds and fungi.
Egg Selection
Check the eggs for cleanliness soon after collection.
Save eggs that are free of clinging dirt or debris and
those with a small amount of adhering dirt that can be
easily removed. Never save dirty eggs for incubation.
They can spread disease to other eggs and chicks.
Incubate only eggs of average size. Excessively large
eggs hatch poorly; small eggs hatch into small,
unthrifty chicks. Do not incubate abnormally shaped
eggs; they probably will not hatch. Discard all cracked
or thin shelled eggs. These eggs do not retain the
moisture needed for proper chick development. An egg
grading is done based on contamination.
-
Clean eggs minimally contaminated - immediately
wash and sanitise.
-
Moderately contaminated, wet and dirty eggs - Put
to one side, wash and sanitise after Grade 1 eggs,
then place on setter trays at the bottom of trolley.
-
Heavily contaminated eggs - dispose of.
Operators must clean hands between handling dirty
eggs and washed or sanitized eggs.
Egg washing
If done it should be as soon as possible after collection
and using solutions that are changed frequently so that
disinfectants are still active. It is very easy for egg
washing incorrectly done to spread bacterial and or
fungal contamination between eggs and to carry
infection through the shell. Heavily contaminated eggs
should not be washed as they will rapidly use up all the
disinfectant and will cross contaminate other eggs.
would be about 14-18oC and a relative humidity of
65-70%. From egg collection to setting, it is vital to
prevent condensation on the eggs and in the
environment as this will allow moulds and aspergillus to
grow. If the atmosphere is too dry then excessive
moisture loss will reduce hatch if storage is prolonged.
If storage is more than 3-4 days then turning the eggs
will help maintain hatchability.
Incubation process
If eggs have been stored at a fairly low temperature
then they should be gradually warmed up
(pre-warmed) prior to incubation. This is mainly to
prevent condensation on the shell which will increase
bacterial infections in the embryos. Pre incubation is
often done by moving eggs from the store to the setter
room. Setters are the incubators used for most of
incubation. The eggs are then usually transferred into
trays and put in a different incubator, a hatcher, for the
last 3 days where they then hatch.
Setters and hatchers are available in many different
models and sizes (Figs 1 and 2). There are two basic
types of incubator, forced-air and still-air incubators.
Still-air incubators are usually small but may hold 100
eggs or more as a single layer. They do not have fans
and hatching will usually also occur in the same
incubator. Forced-air incubators are much larger and
will have internal fans to circulate the air. They can hold
large numbers of eggs which are placed in stacks of
trays. Most units have automatic equipment for turning
the eggs and spray-mist nozzles for holding proper
humidity levels. Setters can be divided into single or
multistage units.
Egg storage
Eggs must be stored and set air cell up (small end
down) or they will not hatch. The longer eggs are
stored the lower the hatchability and the more critical
the storage conditions become. Lower temperatures
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conditions within the incubator should be constant.
If a multi-age setter is loaded once a week with new
eggs when the new eggs are put in the incubator it
can be formaldehyde fumigated, as eggs incubated
for 7 and 14 days will not be harmed by fumigation.
Eggs at 10 days incubation should not be
fumigated with formalin.
In a single stage setter, the eggs are all of the same
incubation age, the conditions are set to vary during
incubation and this should enable conditions at
different stages of incubation to be optimal for
maximum hatch. The setter can be thoroughly
cleaned and disinfected after transfer before the
next set of eggs are placed in the machine. Again,
they can be fumigated when set.
Disease control
The temperatures and humidity of the incubators
and hatchers are ideal for the growth and
multiplication of bacteria, fungi and moulds. It is vital
for the production of healthy chicks that the layout,
management and airflow within the hatchery
prevent these infections. Air must not move from
the hatchers and chick processing areas back to the
egg storage or the setters, as it will carry bacterial
and fungal contamination. All air discharged from
setters and hatchers should be directly out of the
hatchery and this contaminated air must not be
given the opportunity to spread infections through
the hatchery. Very thorough cleaning and
disinfection should be carried out of hatchers and
hatcher rooms between hatches. For larger
hatcheries fogging may be appropriate.
Fig 1 A very old setter and hatcher
Formalin fumigation of eggs before and during
incubation and also empty machines.
For fumigation of eggs prior to storage, it is
common to use 1.35ml of 40% formalin solution and
0.84g potassium permanganate per cubic foot of air
space. Empty incubators and hatchers may be
fumigated using double this concentration. At
setting and during incubation you should use a
lower concentration (0.5ml 40% formalin and 0.2g).
When fumigating ensure that you
appropriate COSHH and H and S in place.
have
Hatcher fumigation
Fig 2 A modern setter in a modern purpose built room
With multistage setters, eggs at various stages of
incubation are held in the incubator and the
During the hatching process a lot of bacteria are
released into the air, also the warm moist hatcher
environment is ideally suited for the multiplication of
pathogenic bacteria. The bacteria can infect the
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newly hatching chicks through the naval or by
inhalation. Many hatchers have fans or are set up
so that a damper can open once most chicks have
emerged and drive fairly large volumes of air
through the hatcher providing a cleaner
environment. Control is partly by the use of
fumigation with formaldehyde gas from the start of
pipping to close to take off. A protocol that works in
many machines is:
60mls of 40% formalin plus 45 mls of water per
cubic metre hatcher volume placed in a container
with an evaporative surface area of 50cm per cubic
meter of hatcher volume. The trays should be put in
the hatcher as soon as piping starts, this will
achieve approximately 20ppm of formaldehyde gas
in the hatcher during piping. Trays should be
removed about 4 hours before pulling the chicks so
as to reduce formaldehyde gas to a safe level for
the operators.
Assessing Incubation
This is done by measuring and recording as many
parameters as possible, from temperature and
humidity in the egg store (Fig 3) for example. Egg
weight loss from setting to transfer should be 12%,
chick weight should be 67% of fresh egg weight.
Hatchability should be monitored for every source of
egg. Egg break-outs should be carried out
whenever hatch is below anticipated and the
proportion of early, mid and late dead determined
(Fig 4). Hatch debris when chicks are pulled should
be assessed for excessive dryness and meconium,
suggesting chicks should be removed sooner from
the hatcher. Candling may be used early in
incubation (day 8) to assess likely hatchability and
also gives the opportunity to remove infertile and
early dead which creates more space in the setters.
Fig 3 Measuring and recording maximum and
minimum temperature and humidity
Fig 4 Trays of eggs from a break out split into early,
mid and late death
To assess causes of poor hatchability, it is useful to
break open the unhatched eggs from a hatch and to
assess the stage of incubation that they have died
at. The normal pattern is about 40% early dead/
40% late dead and the remainder mid dead. Early
dead are usually a consequence of infertility or
incorrect egg storage or transport conditions and
late dead are likely to be due to incorrect incubator
conditions. Mid dead are usually few in number and
often due to bacterial infection, unless there has
been an incubator breakdown ½ way through
incubation. Where there are a lot of early dead it
may be worth candling another hatch at about 8-11
days and doing a break out on the infertile/early
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dead; as these can be differentiated more easily at
this time point.
Summary
In summary, regular monitoring and
recording of incubation inputs, conditions
and outcomes are vital for identifying the
possible causes of problems and in
determining what needs to be changed in
order to improve hatchability. Conditions
during egg collection, egg shell
disinfection,
transport,
pre-storage
incubation, storage, pre-warming or
during incubation are all important.
Inappropriate conditions can result in
reduced hatchability, increased embryo
mortality and poorer post-hatching
performance.
Elanco
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