Incubation 
Contents
 Incubation & its Types
 Obtaining hatching eggs
 Storage and care of eggs prior to incubation
 Location of incubator
 Readying the incubator for operation
 Preparing the eggs for incubation
 21st days developmental stages of embryo
 Final stage of incubation
 Factors affecting the incubation
 Reason for poor hatch

Incubation
“The process of changes of fertile egg to a living organism capable of walking and eating”
 Through Natural incubation at small scale using “Broody Hen” and Artificial incubation at large scale for the commercial purpose using different machines called “Incubator”
is called incubation.
Types of Incubation
There are two types/methods of incubation
1. Natural incubation (Broody Hen)
2. Artificial incubation (Incubator)
1) Natural incubation (Broody Hen)

 The Broody hen is a time tested way to hatch eggs.
 Very good at her job.

 To use a hen for hatching you have to do one of two things
 Find a hen sitting
 Induce a hen to sit

Signs of broodiness
 Clucking
 Stays away from the rest of the flock
 Ruffled feathers
 Aggressive and protective of nest
 On the nest at night
Characteristics
 No electricity required
 Hens does all the work herself
 Will brood chicks after they hatch.
 High hatchability rate
 Some breeds hatch better under hens (Nankin) than in incubators.
 Good for hatching small # of chicks per year.
Drawbacks of natural incubation
 Hens can only sit on a small numbers of eggs at a time
 Hens sometimes break eggs
 Will occasionally quit and get off nest
 Disease transmission from hen to chick

2) Artificial Incubation

Incubator
“An incubator is basically a box that holds eggs while maintaining appropriate temperature, humidity, and oxygen level. Incubators have varying capacities and adapters for eggs from different species.
 Popular incubator models often include

 Automatic turners
 Humidifiers, and
 Temperature controllers

 Incubators comes in

 Forced air incubator
 Still air incubator
The temperature and humidity in a forced air incubator is more consistent. They also return to desired temperature and humidity more quickly after being opened. Still air incubators can give inaccurate humidity and temperature readings and the temperature in them can vary considerably.
Preparation Stage
 Chick incubation process is 21 days
 Gather fertilized eggs 2 – 3 days in advance
 Grading and cleaning of eggs
 Storage of hatching eggs
 Disinfection of hatching eggs
 Location and set up of incubator
 Mark eggs
From Egg to Chick: Incubation Procedures
1. Obtaining and caring of eggs
Gather fertilized eggs from a disease free breeder farm. Obtaining fertile eggs may present a problem, especially if you live in an urban area. Most of the eggs sold in grocery stores are not fertile and cannot be used for incubation. Fertile eggs can usually be obtained from hatcheries or poultry breeding farms.
2. Grading and cleaning of hatching eggs
In selecting hatching eggs, the requirements regarding shell quality and egg shape will be higher for layers than for broilers.
Eggs unfit for hatching are
 Dirty eggs
 Cracked eggs
 Thin shelled eggs
 Eggs with shells, which are rough and not uniform
 Misshapen eggs
 Eggs with abnormal spaces
• Loose or floating air cells
• Too large air cells
 Eggs with large blood or meat spots

3. Storage of hatching Eggs
The hatchability of eggs can be severely reduced by improper care prior to incubation. Since it may not be practical for you to put the eggs in an incubator as soon as you get them, protect them from extreme variations in temperature. Ideally, eggs should not be more than 7 days old when they are set (placed in incubator). Beyond that point, hatchability declines.
If it is necessary to hold the eggs before you set them, turn them daily and keep them in a room where the temperature is around 50◦ F (10◦ C) and the relative humidity is 70 to 80 percent. The vegetable section of your refrigerator could be used for holding the egg until it is time to place them in the incubator. Temperatures below 40◦ F (4 ◦C) reduce hatchability.
 Eggs should be stored at a temperature of around 50°F until incubation begins
 Eggs should not be more than 5-7 days old
 After 7 days, hatchability decreases 0.5 – 1.5% per day.
 Each day in storage adds one hour to the incubation time

4. Disinfection of hatching egg

The disinfection should take place in a specially designed cabinet in which temperature, humidity and the period of disinfection as well as the ventilation can be controlled. As disinfectant formalin can be used .

5. Location of incubator

Locate your incubator in a room in which temperature is between 70 ◦F and 75 ◦F (21 ◦C and 24 ◦C), and which free from drafts and excessive variations in temperature. Do not place the incubator near windows where it will be exposed to the direct rays of the sun. The sun’s rays may raise the temperature so much that all of the embryos will be destroyed. The incubator and hatcher should also be isolated from the growing facilities.

6. Starting the incubator for operation
Sanitize the incubator with detergent or with the combination of detergent and disinfectant and run it for several days before setting the eggs. This will ensure that the incubator is maintaining the proper temperature and relative humidity (2-3) before the eggs are set. Adjusting the temperature and humidity after the eggs are set can decrease hatchability.
Cleaning and fumigation of the incubator
Microbes in an incubator can significantly reduce hatchability. Cleaning and disinfecting equipment must be standard operating procedures. When using a combination of a detergent and a disinfectant remember each combination does not improve the effectiveness of the disinfection. So, disinfect incubators, hatchers and their racks with quaternary ammonium compound or a commercial disinfectant after each hatch.
Preparing the eggs for incubation
Eggs must be turned while in the incubator, so before you put in the eggs mark them with a pencil so you can tell when they have been properly turned. An excellent method is to put an “X” on one side of the egg and a “0” on the opposite side. Then you can always tell when the eggs have been turned, because either all “0”‘s or all “X”‘s are turned up at the same time.

7. The day eggs are set
Let stored eggs warm to room temperature for 4 hours to 8 hours before setting them in the incubator. If you place cold eggs in a warm, humid incubator, condensation will form on them and lead to possible contamination or suffocation. Once the eggs are in the incubator, do not adjust the temperature or humidity for a few hours, unless the temperature exceeds 102°F. After 4 hours, make proper adjustments. The final temperature should vary only 0.5 degree above or below 99.5°F.
Embryonic Development Stages

The development of the embryo can roughly be divided into the following stages:

a. In the hen : Three layers of cells
The names of the layers are:-
i. Endoderm, which gives rise to the respiratory and secretary organs and to the lining of various parts of the digestive tract
ii. Ectoderms, which are the basis for the skin, the beak, cloacae, eye and nervous
system
iii. Mesoderm (third layer): from this layer originates the bones, blood excretory and
reproduction organs.
b. During incubation:

 1st – 4th day : initial stage of inner organs
 5th – 14th day : initial stage of outer organs
 15th – 20th day : growth of the embryo
 21st day : hatch of the chicken
Summary of the embryonic development from day to day
Stage I: Development of the internal organs
 1st day : enlargement of the blastodisc
 2nd day : heart starts beating, tiny bloodspots appear
 3rd day : initial stage of the beak, legs, wings
 4th day : initial stage of the tongue
 5th day : shaping on the reproduction organs
Stage II: Development of the external organs
 6th day : beak gets shape
 8th day : shaping of the feathers
 10th day : hardening of the beak
 13th day : shaping of the leg scales and claws the size of the allantois reached its maximum
 14th day : the structure of the embryo is completed the embryo settles for its final position
Stage III: The growth of the embryo
 15th day: leg scales and claws become horny from the 15th – 19th day the intestines are withdrawn into the body cavity. The neck bends forwards
 16th day : the contents of the allantois has disappeared completely
 17th day: the beak directs itself toward the air cell the fluid of the amnion continues to disappear. This will be finished at the 19th day
 19th day : the yolk is being withdrawn into the body cavity the air cell gets penetrated by the beak
 20th day : the yolk is withdrawn, the embryo fills the whole egg, excluding the air space the eggshell is fractured
 21st day : the chicks is hatched
8. Candling
“Shining a light through the egg to observe embryo development is called candling.”
White or pale eggs are easier to candle than dark or spotted eggs. Embryos can be confirmed easily after 8 to 12 days of incubation. The living embryo will appear as a dark spot in the large end of the egg surrounded by a faint outline of blood vessels. The embryo appears as dark spot that becomes larger as incubation progresses. Eventually you will see only a dark mass and the air cell.
In comparison,
An infertile or un-incubated egg transmits light brightly. Dead embryos will sometimes appear as a ring or a smear of blood in the egg or a dark spot dried to the inside of the shell. Once it dies, the embryo no longer grows and the blood system fades. Cooling that occurs for less than 10 minutes during candling does not harm the embryo.
9. Hatch stage
This stage refers to final 2 to 3 days of incubation when chicks hatch out of the shell. Transfer eggs to a dedicated hatcher for the last 3 days to 4 days of incubation and do not turn them. During this stage, decrease the temperature 1°F and increase the relative humidity to 65-70%. You can increase the humidity by adding a wet sponge or wet paper towels to the incubator.
10. Final Stages of Incubation
After the 17th day the eggs should not be turned. Incubator should not be opened unless it is necessary to add water. Chicks will start to pip the shell around the 19th day. All chicks which are going to hatch should be out of their shells by the 21st day.
Managemental factors for the incubation and hatching process
For a special incubation and hatching the following factors are of major importance:
1. Temperature
2. Humidity
3. Ventilation
4. Turning
1. Temperature
During incubation till 18th days the temperature should be 99.5◦-100◦ F. In the hatcher the temperature should be 98.5 – 99◦ F. Make sure of a constant temperature and regularly check the thermometers of deviations. Too high as well as a too low temperature has influence on the hatching results. Check the temperature at least twice a day.
2. Humidity
The ideal moisture level is about 50 – 55% relative humidity (83o – 87o F (28 – 31o C) on a wet bulb thermometer) for the first 18 days. About 65 % (89o – 90o F (31 – 32o C) wet bulb) for the last 3 days. Excessive drying because of low humidity will cause the chick to stick to the shell and fail to survive. To increase the humidity level the last three days, set an extra pan of water in the incubator.
3. Ventilation
A correct functioning of the ventilation system is needed:
 To supply oxygen (O2)
 To discharge carbon dioxide (CO2)
 To distribute the heat evenly
 The carbon dioxide content inside the hatchery should never exceed 0.5%.

4. Turning of eggs
During the incubation period (1-18days) the hatching eggs need regular turning (90o) to prevent that the embryos from sticking to the shell membranes. As it will do if it is left in one position too long. Turn the eggs at least (2-3) times a day.
Reason for poor Hatch
 Infertile eggs
 Eggs too old when set
 Parent stock weak, unhealthy, or fed a nutritionally deficient diet
 Improper care of eggs prior to incubation
 Shell contamination
 Temperatures too high, too low, or too variable during incubation
 Too little humidity in the incubator or occasionally too much
 Improper ventilation
 Oxygen starvation