Incubation is the act of bringing an egg to hatching. It refers to the process by which certain oviparous ( egg-laying) animals (birds) hatch their egg. It also refers to the development of an embryo within the egg under favourable environmental condition. Incubating chicken eggs is a 21- days process and demands favourable conditions of principal affecting factors like temperature, humidity etc.,  Incubation may be of two different types: 1. Natural Incubation 2. Artificial Incubation

1. UNIVERSITY OF AGRICULTURAL
SCIENCES, GKVK,BENGALURU
EL/HOT : EAS421: POULTRY
PRODUCTION TECHNLOGY
[0+10]
INCUBATION REQUIREMENTS OF
POULTRY
KUSHI NAVIN
ALB7088

2. INCUBATION
Incubation is the act of bringing an egg to hatching. It refers to the process by
which certain oviparous ( egg laying) animals (birds) hatch their egg. It also refers to
the development of embryo within the egg under favourable environmental condition.
Incubating chicken eggs is a 21- days process and demands favourable
conditions of principal affecting factors like temperature, humidity etc.,
Incubation may be of two different types:
1. Natural Incubation
2. Artificial Incubation

3. NATURAL INCUBATION
. Incubation by
Incubation by setting a broody hen over eggs is called
natural incubation. In this method broody hens are made
to sit over hatching eggs to a longer period without feed
and water due to some hormonal changes.
* The full incubation period for an egg from laying to
hatching is 20-21 days.
* During this time , a hen sits on her eggs and maintains a
temperature required to ensure proper embryonic
development.
TERMS RELATED TO NATURAL INCUBATION
Brooding:
In poultry , the act of sitting on eggs to incubate them is
called Brooding.
Broodiness:
The action or behavioural tendency to sit on a clutch of
eggs to incubate them is called Broodiness. Prolactin
is a hormone that is mainly responsible for broodiness in
hen.

4. The broody hen chosen for natural incubation should be large enough to cover and
thus keep more eggs warm, healthy and preferably vaccinated with a good brooding
and mothering record. Incubation under a broody hen is the ideal way to hatch a
small number of eggs . A hen can successfully hatch 12-15 eggs depending on her
size.
Signs of broodiness in hen:-
1. Clucking
2. Stays away from the rest of the flock
3. Ruffled feathers
4. Aggressive and Protective of nest.
5. Remains sitting on her eggs.
A hatchability of 80% (of eggs set ) from natural incubation is normal but a range
of 75-80% is considered satisfactory.
ADVANTAGES
1. No electricity
2. Hen does all the work
3. Some breeds hatch better under natural incubation than under
incubators.
4. Good for hatching small number of chicks per year.
5. High hatchability rate.
DISADVANTAGES
1.Hen sometimes breaks the eggs
2. Will occasionally quit and get off the
nest
3. Can only sit on small number of eggs
4. Disease transmission from hen to
chicks.

5. BREEDS THAT HAVE GOOD MOTHERING CHARACTER

6. ARTIFICIAL INCUBATION
Incubation independent of the hen i.e. by means of mechanical
equipment (incubator) is known as artificial incubation.
HISTORY
* Artificial incubation of poultry eggs is an ancient practice. In 400
B.C. Aristotle mentioned of Egyptians incubating the eggs
spontaneously in dung heaps.
* The Chinese developed artificial incubation technique as early as
246 B.C.
* These early incubation methods were often practiced on a large
scale, a single location perhaps having capacity of 36,000 eggs.
* Incubation can successfully occur artificially in machines that
provide the correct, controlled environment for the developing
chick. Such machines are known as incubators.
* The construction, use and patent of artificial incubators dates back
to 1844. The Smith incubator is the forerunner of today’s large
scale incubators used for hatching eggs.

7. INCUBATORS
Incubator is a device used for maintaining the eggs of birds and allows them to hatch. It
provides the optimum environmental conditions for successful hatching of eggs.
TYPES OF INCUBATORS
Based on air circulation Based on Size
1. Still air incubators 1. Cabinet or Mammoth incubator
2. Forced air incubators 2. Walk in incubator
Based on stages Based on heating source
1. Single stage incubator 1. Hot air incubator
2. Multi stage incubator 2. Hot water incubator

8. Based on Air Circulation:
Still Air Incubator:
* It is a simple type of box in which no fan is provided, mostly used in villages in
domestic level.
* Temperature is maintained by thermostat at around 102 degree c
* Small holes are made for air (ventillation).
* To maintain humidity water trays are used in the incubator and is maintained at
60-65% (80-90° wet bulb) during incubation and 70-75% (92-97° wet bulb) at
hatching time. It is very easy to overheat the eggs in still-air incubators and
difficult to maintain proper humidity
Disadvantages:
* Hatchability can be low.
* Hard to regulate temperature and humidity.
* Can have high number of deformities in chicks.

9. Forced Draft Incubator:
* In this type of incubator, air is forced with the help of a fan and the drafted air is
uniformly distributed.
* Temperature remains constant on each egg, for the control of temperature heater
or thermostat is provided and even coil heating mechanism is used
* For maintainence of humidity water piper and humidity pans are used. Fogging
modifier is provided which spray fog type air. Hygrometer is used to meaasure
humidity.

10. Based on size:
Mammoth / Cabinet incubator:
Mammoth means large in size and the mechanism of operation is force draft in which air
is forced by the help of fan. It is also called cabinet incubator since it has several definite
compartmentalisation. It works on forced draft mechanism.

11. Walk - in incubator:
It is large in size that a man can walk in it . The capacity of walk-in incubator is 1
lakh - 5 lakh eggs. Temperature is set automatically and for ventillation large number of
fans are provided.

12. Based on Stages of Incubator
Single Stage Incubator:
A single stage incubator contain setter and hatcher in a single chamber. There is no separation
between setter and hatcher.
Multi Stage Incubator:
A multi-stage incubator contains setter and hatcher in separate chambers.
Single Stage Incubator Multi Stage Incubator

13. PRE- SETTING MANAGEMENT OF INCUBATORS :
Washing :
After each batch, after pulling out the hatch, the dust, dirt, feathers, down etc
should be removed completely and the trays should be removed and washed with
pressure water. Trays should be scrubbed and washed separately.
Disinfection :
After cleaning with plain water, the incubator and the spares should be cleaned
with any disinfectant solution and then with 4% washing soda solution.
Fumigation :
Sensitive spares like thermometer, humidity controls should be removed before
fumigation. The tray containing the fumigation mixture ( 20 gms KMn04 + 40ml
formalin = 1X concentration of formaldehyde gas which is sufficient for fumigating
100 Cu ft area) should be kept on the floor of the incubator. All the inlets and outlets
of the machine should be closed and the gas is trapped for 3-4 hours. After 3-4 hours,
the doors
Test run:
Before actually setting the eggs in the incubator, the machine should be switched
on to check the working condition of the temperature, humidity, ventilation and
turning devices of the incubator.

14. POST-SETTING MANAGEMENT OF INCUBATORS :
After setting the eggs in the incubator, following points to be noted :
* Do not open the doors of the incubator frequently because it alters the conditions
within the incubator.
* Frequently check for the temperature, humidity levels in the incubator.
* Monitor the turning device and the flow of warm water in pipes.
* Shifting of egg from setter to hatcher on 18th day should be as quick as possible.

15. INCUBATION REQUIREMENTS OR PRINCIPLES
There are seven factors of major importance in incubating eggs artificially:
* Temperature
* Humidity
*Ventilation
* Incubation period
*Position of eggs and turning
*Setters and Hatchers
*Testing of eggs (candling)

16. TEMPERATURE
Temperature is the most critical environmental concern during incubation.
The optimum temperature ranges between 98.6° F and 100.4° F (37-38° C) in forced
draft incubators and 10 F higher in still air incubator. Maintenance of the optimum
and uniform temperature in the incubator is essential for successful incubation
leading to good hatchability. Required temperature will be maintained with the aid of
heat generating coils and the temperature is measured using thermometer.
Overheating is more critical than under heating. Running the incubator at
105°F for 15 minutes will seriously affect the embryos, while running it at 95°F for 3
or 4 hours will only slow the chick's metabolic rate.
* Too high temperature results in excessive late embryonic mortality.
* Low setter temperature result in slow embryo growth , late and uneven hatching
and high percentage of unhatched eggs.

17. TEMPERATURE REQUIREMENT OF DIFFERENT
SPECIES
Species
Temperature (0C)
Setter Hatcher
Chicken 37.7 37.2
Turkey 37.4 36.9
Duck 37.5 37.1
Muscovy duck 37.5 37.1
Geese 37.4 36.9
Pigeon 37.4 37.2
Quail 37.4 37.2
Bobwhite quail 37.4 37.2
Chukar partridge 37.4 37.2
Pheasants 37.6 37.2
Guinea fowl 37.6 37.2
Ostrich 36.0 35.6
Emu 36.0 35.4

18. HUMIDITY
Humidity is also important because the rate at which eggs lose water by
evaporation depends on the ambient relative humidity. The RH should be 55-60 %
during first 18 days and may be increased to 75 % during last 3 days of incubation.
For this wet bulb thermometer is to be used as guide. The wet bulb thermometer
reading of 85° F will indicate RH of 55 %. and 95° F will indicate 70 % humidity.
Humidity will be maintained either by a tray filled with water kept at the bottom of
the incubator or by circulating warm water in pipes.
Too much moisture in incubator prevents normal evaporation and results in a
decreased hatch, chick with a large yolk and a sluggish chick which is difficult to
save. Too little moisture result in excessive evaporation, causing chicks to stick to the
shell , remain in the piped shells and sometimes hatch crippled.

19. HUMIDITY REQUIREMENT OF DIFFERENT
SPECIES
Species
RH (%)
Setter Hatcher
Chicken 55 75
Turkey 55 75
Duck 57 80
Muscovy duck 57 78
Geese 58 80
Pigeon 56 76
Quail 56 76
Bobwhite quail 56 76
Chukar partridge 56 76
Pheasants 57 76
Guinea fowl 57 76
Ostrich 30-35 40-45
Emu 40 50

20. VENTILATION
Ventilation is crucial because the embryo is a living organism which exchanges
oxygen and carbon dioxide through the shell during the incubation process. The
amount of air exchange needed increases as the embryo develops. As the embryo
develops, it uses oxygen and gives off carbon dioxide. Thus, sufficient ventilation
within the incubator is required to assure an adequate supply of oxygen and proper
removal of carbon dioxide. The optimum concentration of oxygen is 21 %. Oxygen
concentration above or below 21 % negatively affects hatchability. Likewise the
carbon dioxide concentration should not exceed more than 0.5 %. Proper ventilation
is maintained with the help of fans fitted to the rear side of the incubator.
The vents which are located above and below the eggs should be opened
gradually until they are fully opened during the final three days of incubation.
Ventilation rates that are too low prevent normal moisture evaporation and cause
large weak chicks or death. High ventilation rates remove too much moisture and can
cause the shell to stick to the chick, making hatching difficult. 1000 eggs require
143ft3 of fresh air per day ( oxygen in the air at 21%) on the 18th day of incubation.
Hatchability will drop about 5% for each 1% drop of oxygen content in the air
below 21%. Gaseous exchange rate during incubation varies with the age of embryo.

21. GASEOUS EXCHANGE DURING INCUBATION

22. POSITION OF EGGS AND TURNING
Eggs are always set in the broad end up position. Eggs should be turned minimum
6 times a day between the second and 18th day of incubation. Automatic turning of
the trays in the setter is brought about with the electric motor fitted with clock.
However, in fully automatic incubators, turning is done once in an hour. The turning
process allows the embryo to revolve and slide in the inner white ,yolk does not stick
to the shell membrane.
CARE TO BE TAKEN IN TURNING OF EGGS
* For good hatchability , eggs should be turned to a position at least 45 from the
vertical , then reversed in the opposite direction to a similar position.
* Eggs should not be turned in a complete circle, as this has a tendency to rupture
the allantois sac with resultant embryonic mortality.
* Eggs should not be turned in either large or small incubators during the hatching
period.
* Use care in turning eggs to avoid shocks or jars that may rupture the blood vessels
of the germ.

23. * Place turner on the bottom incubator with the motor side to the back of the
incubator ( rim of bottom with notches is the back). Slide turner as close as
possible to the front rim of bottom of incubator. Be sure the turner sits flaton wire
floor.
IMPORTANCE OF TURNING
* The purpose of this turning is to prevent the germ spot from migrating through
the albumen and becoming fastened to the shell membrane.
* Turning the eggs prevents an adhesion between the chorionic and shell
membrane.
* Turning is essential for the survival of healthy chick.

24. SETTERS AND HATCHERS
Two separate machines are used during the incubation process.
SETTERS:
The setter is designed to initiate the incubation of cold endothermic eggs during
the first 18 days of the hatching process. Requiring a lot of heating at first, the
embryos will grow and become exothermic. At this point , they will require a lot of
cooling instead as they will produce a lot of heat themselves.
HATCHERS:
On day 18, eggs have to be transferred from the setters to the hatchers. The
hatchers will have a lot of heating. Hatcher and hatcher baskets always should be dry
before they are used. As soon as the eggs are in it from day 18 to 21, the hatcher will
mainly cool down because he developing chicks produce the most amount of heat. In
this stage, it is crucial to avoid risks of overheating or overcooling else, it may resullt
in head over wing malposition which results even when there is uneven cooling
process due to lack of air flow.

25. SETTERS HATCHERS

26. CANDLING ( TESTING OF EGGS)
Assessing the internal quality of an egg without breaking open the egg, by
holding it against a source of light. It is a way of checking the fertility of an egg and
to observe the growth and development of an embryo inside an egg which uses a
bright light source behind the egg to show details through the shell.
EGG CANDLER: An egg candler is a simple device used for testimg eggs. It is
so called because the original sources of light used were candles. Modern egg
candlers or candling lamps are lights with a concentrated beam.
SPOT CANDLERS MASS CANDLERS

27. SCHEDULING OF CANDLING
There are two critical stages during the incubation period of 21 days, first
between 2-4thday when about 16 % mortality may occur due to faulty heart formation
referred as EED and second one during 18-19 days of incubation, where due to
abnormal position of embryos, and they are changing from poikilothermy to
homoeothermy at this stage they above to start their pulmonary respiration, about 48
% of the total mortality takes place. Testing of eggs is therefore done by candling
from 5-7th day of incubation to remove infertile eggs while on 18th day when the
eggs are ready to transfer in hatching trays to discard dead embryos.
Hatching eggs will be subjected to candling thrice i.e.
1st candling - before setting the eggs
2nd candling - 6-8 days of incubation
3rd candling - 18th day of incubation (before shifting the eggs from setter to hatcher)
PURPOSE OF CANDLING
Candling allows to monitor :
* Egg fertility
* Embryo development
* Weight loss rate
* Remove non viable eggs
* Avoid the risk of rotten egg exploding and contaminating
the entire hatch with germs.

28. DEFECTS OF YOLK IDENTIFIED BY CANDLING
* broken vitelline membrane
* mottled yolk
* floating yolk
* presence of blood/ meat spot.
CANDLING RESULTS:
FERTILE EGGS: The egg will appear to have black spot which as the embryo
grows and incubation continues will grow larger until the light will only pass through
the air cell end of the egg. Correctly hatching eggs will show red lines radiating from a centre
spot in spider like appearance. Movement of centre spot is also seen. The air cell is of size of
about a rupee coin.
INFERTILE EGGS: Eggs appear clear.
DEAD EMBRYO: If the egg is fertile but the embryo has died , a blood ring is
seen around the yolk or possibly a dark spot depending on when the embryo stopped
growing.

29. CANDLING RESULTS OF VIABLE HEALTHY EGGS

30. MALFORMED OR PROBLEMATIC EGGS CANDLING

31. INCUBATION PERIOD
The incubation period varies for different species of birds. Generally, the larger
the egg, longer will be the incubation period. Several developmental changes occur in
the embryo leading to final hatching.
Species Incubation period (Days)
Chicken 21
Turkey 28
Duck 28
Muscovy duck 35-37
Geese 28-34
Pigeon 17
Quail 18
Bobwhite quail 23-24
Chukar partridge 23-24
Pheasants 23-28
Guinea fowl 28
Ostrich 42
Emu 52

32. EMBRYONIC CHANGES THAT OCCUR DURING THE
INCUBATION PERIOD
DAY 1: Appearance of embryonic tissue.
DAY 2: Tissue development very visible. Appearance of blood vessels.
DAY 3: Heart beats. Blood vessels very visible.
DAY 4: Eye pigmented.
DAY 5: Appearance of elbows and knees.
DAY 6: Appearance of beak. Voluntary movements begin.
DAY 7: Comb growth begins. Egg tooth begins to appear.
DAY 8: Feather tracts seen. Upper and lower beak equal in length.
DAY 9: Embryo starts to look bird-like. Mouth opening occurs.
DAY 10: Egg tooth prominent. Toe nails visible.
DAY 11: Cob serrated. Tail feathers apparent.
DAY 12: Toes fully formed. First few visible feathers.
DAY 13: Appearance of scales. Body covered lightly with feathers.
DAY 14: Embryo turns head towards large end of egg.
DAY 15: Gut is drawn into abdominal cavity.
DAY 16: Feathers cover complete body. Albumen nearly gone.
DAY 17: Amniotic fluid decreases. Head is between legs.
DAY 18: Growth of embryo nearly complete. Yolk sac remains outside of embryo.
Head is under right wing.

33. DAY 19: Yolk sac draws into body cavity. Amniotic fluid gone. Embryo occupies
most of space within egg (not in the air cell).
DAY 20: Yolk sac drawn completely into body. Absorption of allantoic fluid is
completed Embryo becomes a chick.
DAY 21: The chick uses its wing as a guide and its legs to turn around and pierce the
shell in a circular way by means of its egg tooth . It extricates itself from the shell in
12 to 18 hours and lets its down dry off.