Incubation requirement

Incubation Incubation refers to the process by which birds hatch their eggs,

and to the development of the embryo within the egg.

The most vital factor of incubation is the constant temperature required for its development over a specific period.

The average incubation period for chickens is 21 days

TypesThere are two types of incubation

Natural incubation

Artificial incubation

Natural incubation 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

Artificial incubation Use of a machine which warms, turns, humidifies bird eggs to incubate and eventually hatch them.

Requirement of incubation

These are the major requirement of incubation

Temperature

Humidity

Ventilation/ air

Turning

Temperature Temperature is the most critical environmental concern during

incubation

During setter phase temperature required is 98.5-100.5⁰F( 37.2-38.3⁰C)

During Hatcher phase temperature required is 98-99⁰F (37-37.5⁰C)

Cont… When incubation temperature deviate from the optimum level,

hatchability will decline And the incidence of the malformed chicks will

increase

Too high temperature results in excessive late embryonic mortality

Low setter temperature result in show embryo growth, late and uneven

hatching, and high percentage of unhatched eggs.

Temperature requirement of different species

Species Temperature (°C)Setter phase Hatcher phase

Chicken 37.2-38.3 37-37.5

Turkey 37.5 37.0 O

Geese 37.7 37.5

Duck 37.5 37.2

Japanese quail 37.5 37.1

Pheasant 37.5 37.1

Ostrich 36.1 – 36.7 36.0 - 36.7

Humidity Humidity is also important because the rate at which eggs lose water by evaporation depends on the ambient relative humidity

The relative humidity of air with in incubator should be about 60%

During the last 3days the relative humidity should be nearer 65-70%

Cont… 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 pipped shells, and sometimes hatch crippled

Chick with a large yolk

Humidity Requirement of different species

Species Humidity (%)Setter phase Hatcher phase

Chicken 55 65

Turkey 55 75

Goose 50-55 75

Duck 55 65

Japanese quail 60 70

Pheasant 65 90

Ostrich 20 – 40 60 – 70

Ventilation/ air Proper ventilation is important for successful incubation

Insufficient ventilation may result in embryo or chick death

During the hatching period additional ventilation must be supplied to reduce the carbon dioxide in the incubator

Each process is speeded up approximately 100 times between the first and 21st day of incubation

Ventilation Since 1,000 eggs require 143 ft3 of fresh air per day (oxygen in the air at 21%) on the 18th day of incubation

As the embryo grows it needs a larger supply of fresh air

The movement of gases through the pores of the shell and the shell membranes is important because the developing embryo must receive a constant supply of oxygen and must eliminate carbon dioxide and moisture.

Oxygen in the Air oxygen content of the air in the setter and Hatcher remains at about

21%, but there may be some variation in the hatcher where large

amounts of carbon dioxide are produced by the newly hatched chicks

Hatchability will drop about 5% for each 1% that the oxygen content of

the air drops below 21%.

Gaseous exchange during incubation

Day of incubation Absorption of oxygen(ft3)

Expulsion of carbon dioxide(ft3)

1 0.50 0.29

5 1.17 0.58

10 3.79 1.92

15 22.70 11.50

18 30.00 15.40

21 45.40 23.00

Turning The turning process allows the embryo to revolve and slide in the inner white, yolk does not adhere to the shell membrane and provides access to additional nutrients for embryonic development.

If turning is not occur in the incubator Deforming of the inner membrane started and eventually the yolk will touch the shell membrane

Cont… If it happens embryo uppermost the embryo will stuck the shell and die

For this reason turning is essential for the survival of healthy chick

For good hatchability, eggs should be turned to a position at least 45 from vertical, then reversed in the opposite direction to a similar position

Egg turning should be undertaken 6-8 times per day

Cont… 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.

References http://www.avianweb.com/images/products/brinsea/incubation.pdf

Joseph M. Mauldin, Extension Poultry Scientist at the University of Georgia explains the exchange of oxygen, carbon dioxide and moisture in the egg during incubation in the Spetember 2003 issue of the University's Poultry Tips

Handbook of poultry production (A Brief Encyclopedia)

Commercial chicken meat and egg production 5th edition

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