INCUBATION and HATCHING

-1- History

The beginnings of artificial incubation date back some 4,000 years before our era. The Egyptians and the Chinese were the first to practice it. It was not until the beginning of the 20th century that the first incubators appeared in the United States. In Morocco, the first incubators appeared in 1970 for the production of flesh-type chicks and in 1981 for hatcheries for the production of bridge-type chicks. Currently Morocco has 45 hatcheries (40 flesh type and 3 egg type)

I-2- Definition of incubation

Incubation also known as brooding is the act of bringing the eggs to hatch. It can be natural (brooding) or artificial. In some species, artificial incubation cannot be practiced; this is the case with the pigeon.

I-3- Incubation time

The incubation period varies according to: the species, the strain, the physico-chemical conditions, the shelf life of the eggs, the age of the breeders and the machines. The incubation time in the different species is given in Table 1 below.

Table 1: Incubation time of different poultry species

Poultry species

Period of incubation (en D)

Hen

Turkey

Guinea fowl

Barbary cane

Common Cane

Goose

Pheasant

Gray partridge

Red partridge

Quail

Pigeon

Ostrich

II- HATCHERY DESIGN

II-1- Objective

The objective of artificial incubation is to obtain the maximum of fertile eggs, the maximum of hatching chicks and the maximum of marketable chicks

II-2- Location

The hatchery installation site must be far enough away and removed from livestock buildings and all other poultry establishments (feed factory, slaughterhouse) and also must be sheltered from returning winds from polluting buildings. Ease of access is also a criterion to keep in mind.

II-3- Sketch

The hatchery should be divided into well-separated, well-partitioned and well-sealed rooms. It contains two compartments: a clean compartment contains the eggs and a dirty compartment containing the chicks. In fact, the incubation room is the cleanest room and the hatching room the dirtiest room. It is recommended that the hatchery has several incubation and hatching rooms in order to establish a regular crawl space and properly manage the production schedule. Hatching waste and clear eggs will be disposed of through special doors.

III- TECHNICAL CONDUCT OF INCUBATION AND HATCHING

III-1- Preparation of hatching eggs

After receiving the hatching eggs from breeding farms, the eggs undergo several operations relating to sorting, washing treatment and disinfection and packaging.

III-1-1- Sorting of eggs

The criteria used to sort the eggs suitable for incubation are: the weight of the eggs, the cleanliness, the shape, the quality of the shell and the color of the shell.

a- Egg weight

The minimum weight of eggs that can be incubated in different poultry species is around 60 for the hen, 68grams for the turkey, 48grams for the guinea fowl, 70grams for the duck and 15grams for the quail. Remember that the weight of the hatching chick is positively correlated with the weight of the egg.

b- Egg cleanliness

Eggs with droppings or other improper stains are removed from the incubation process to avoid the risk of contamination of the embryo.

c- Egg shape

The normal egg has an ovoid shape with a small end and a large end. Thus all eggs with deformations: too tapered, elongated ringed ringed are removed from incubation.

d- Quality of the shell

Broken, porous, cracked, micro-cracked, fragile and thin-shelled eggs are eliminated because these defects affect the internal quality of the egg and therefore the viability of the embryo.

e- Shell color

The coloring of the shell is a genetic character which in no way prejudges the internal quality of the egg. However, a healthy egg must take on the recognized coloration of the high strain .

III-1-2- Treatment of eggs

The different treatments undergone by hatching eggs relate essentially to washing and disinfection operations.

a- Washing disinfection

The interest of washing is to remove the cuticle and all the impurities of the shell and to kill the germs which are on the surface of the shell and especially inside the pores. The method consists in passing the eggs through a tunnel where they are sprayed with different solutions according to the following steps:

· Washing bath with detergent at a temperature of 42 ° C,

· Rinsing with water at a temperature of 44 to 46 ° C,

· Disinfection bath using quaternary ammonium at a temperature of 48 ° C,

· Drying

The duration of the operation is on average one minute.

b- Washing-soaking: Dipping

The soaking wash also called dipping is an operation which consists in making penetrate inside the egg a solution containing an antibiotic which has the role of breaking the cycle of certain diseases transmitted vertically by the egg for example the mycoplasmas. The method can be considered in two ways:

· Either by temperature difference: the eggs are preheated to the incubation temperature and which are then soaked in a cold solution. By temperature difference, the eggs contract and the solution is sucked through the pores.

· Either by pressure difference for 15 minutes.

After draining, the eggs are dried and are stored or incubated as quickly as possible.

III-1-3- Packaging of eggs

a- Storage parameters

The standards to be observed for proper storage of hatching eggs are summarized in Table 2 below.

Table 5 : Storage standards for hatching eggs

Storage time	0 to 4 days	5 to 7 days	8-14 days
Temperature (° C)	1 7-18	16 - 17	14 - 16
Relative humidity (%)	80	85	85
Position	Tip down	Tip down	Point up
Packaged	No	Yes	Yes

b- Consequence of long storage

The consequences of long storage are characterized by a drop in fertility, a drop in the hatching rate (see Figure 1), a decrease in the quality of the chicks and an increase in costs. On the other hand, each day of storage results in an extension of the incubation period from 45 to 50 minutes.

Figure 1 : Effect of shelf life of eggs on hatchability

III-2- Conducting the incubation

The placement of eggs in the incubation room requires the control and mastery of the following parameters: the position of the eggs, the temperature, humidity, aeration and turning.

III-2-1- Positioning

The eggs are placed in the incubators, the inner tube at the top.

III-2-2- Temperature

a- Role

The purpose of temperature is to trigger and maintain the multiplication of embryonic cells. Indeed, the hatching egg is endothermic at the start of the incubation for the first 9 days and then becomes exothermic. Indeed, a chicken egg produces around 30 calories during the incubation.

b- Standards

The recommended incubation temperature standards for the different poultry species are shown in the following table.

Table 4: Incubation temperature standards

Poultry species	Hen	turkey	guinea fowl	Goose	Cane
Incubation temperature (° C)	37 ° 75	37 ° 6	37 ° 5	37 ° 6	37 ° 4

c- Effect of non-compliance with standards

Outside the norms, an excessive or insufficient incubation temperature gives rise to the consequences raised in Table 5 below.

Table 5: Consequence of non-compliance with standards

Incubation temperature (in ° C)		Consequences
Excess	37 ° 95	Advanced hatching, smaller chicks.
	38 °	High embryonic mortality.
	38 ° 2	Incubation impossible, death of all embryos between the 20th and the 48th by bursting of the blood vessels.
Insufficiency	37 ° 7	High embryonic mortality, delayed hatching of 3 to 4 hours
	37 ° 6	High mortality rate, hatching delayed 6 to 8 hours, qualities of the chick affected
	37 ° 4	Significant embryonic mortality, hatching delayed by 12 hours, 2nd choice chick.

III-2-3- Humidity

a- Role

The humidity inside the incubators has the role of facilitating hatching and digging, in addition it influences the weight of the chick.

b- Standards

For the different poultry species, the value of the relative incubation humidity is between 50 and 60%.

c- Effect of non-compliance with standards

An atmosphere that is too humid or dry inside the incubators has the effects listed in Table 6 below.

Table 6: Consequence of non-compliance with standards

Excess

Insufficiency

- Bigger, heavier chick

- Swollen abdomen,

- Less vigorous chick,

- Higher percentage of unhatched hatched eggs,

- Risk of omphalitis,

- Difficulty hatching,

- Dehydrated, smaller subjects,

- Drier shell membranes that stick to the embryo,

- Shorter down,

III-2-4- Aeration

The hatching egg is a living being that breathes. So it will need oxygen and remove carbon dioxide. Indeed, the chick consumes 7 grams of oxygen and produces 8 grams of carbon dioxide. Normal rates in incubators are 21% for oxygen t 0.3% for carbon dioxide.

III-2-5- Turnaround

a- Purpose

The purpose of the inversion operation is to prevent the embryo from sticking to the shell, to reduce the abnormal positions of the embryo and also to allow better distribution of heat over the entire surface of the eggs.

b- Modality

Turning the eggs is an operation which is carried out at an angle of 45 °. The eggs are automatically turned every two hours or every hour.

c- Effect of the turnaround on the hatching rate

the effect of the turnaround on the hatching rate is given in table 7 below.

Table 7: Effect of flipping on hatching rate

Turnaround time

Hatching rate (%)

No flipping

First 7 days

First 14 days

III-3- Transfer and mirage

III-3-1- Transfer

The transfer is an operation which consists in passing the eggs from the incubation room to the hatching room between the 17th and the 19th day in the hen, the 25th day in the turkey and between the 23rd and 24th day in the guinea fowl. It is advised that this operation should be carried out with great possible precaution without mechanical or thermal shock so as not to disturb the proper progress of the incubation. The transfer mode can be manual or automatic, but the latter offers several advantages of being faster, allows better positioning of the eggs on the hatching trays, less boredom for the staff and improves the hatching rate. . During the transfer, we take advantage of performing the candling operation at the same time.

III-3-2- Mirage

a- Definition

Candling is an operation which consists in candling eggs with the help of a device called mireuse or test pattern egg to make sure of the state of its content. It can be total or partial. It is total when the rate of clear eggs exceeds 5% and it is partial when this rate is less than 5%. This operation must be carried out as quickly as possible without shock, neither mechanical nor thermal, so as not to disturb the good progress of the incubation.

b- Purpose

The candling operation is essential. The objective is to detect clear eggs; ie unfertilized eggs but also early embryonic mortalities and rotten eggs.

c- Interest

The candling operation is carried out for the following reasons:

- Space saving in incubators and hatcheries,

- Facilitate the proper functioning of incubation and hatching,

- To obtain a better quality of the chick at hatching,

- Ensure better waste management,

d- Modality

The mireuse consists of a light source which is directed towards the eggs. By transparency, we observe the evolution of the embryo. A first candling is carried out on the 6th day of incubation to eliminate the unfertilized eggs. This makes it possible to make a little room in the incubators and especially to calculate the percentage of fertilized eggs to possibly act on breeding farms; especially roosters if this rate is not satisfactory. At this stage of development, we can clearly see a small dark spot, which is the embryo, from which blood vessels form, forming a spider web. In an unfertilized egg, there is nothing. A second candling is carried out around the 18th day of incubation to remove the dead embryos.They are distinguished from living embryos because they are immobile and form a compact mass without vessels.

III-4- Hatching

As in the incubation rooms, placing the eggs in the hatching room also requires controlling and mastering the parameters linked to the positioning of the eggs, the ambient conditions but without turning .

III-4-1- Position of the eggs

Positioned with the tip down (air chamber above) in the incubators, the eggs are laid down and laid flat in the hatchers in crates provided for this purpose.

III-4-2- Temperature and humidity

The temperature and humidity standards in the hatcher recommended for the different poultry species are presented in Table 7 below.

Table 8: Temperature and humidity standards in the hatcher

Poultry species	Temperature (in ° C)	Humidity (%)
Hen	37 ° 6	60% - 85% - 55% + drying
Turkey	37 ° 4	60% - 85% - 55% + drying
Guinea fowl	37 ° 1	60% - 85% - 55% + drying
Goose	37 ° 1	100% + drying
Cane	36 ° 8 - 37 °	68% - 90% - 76% + drying

For chicken eggs, the temperature standards will be 29 ° C at the start of hatching, 34 ° C at 50% digging and brought down to 30 ° C 12 hours before the chicks come out. For humidity, 55 to 60% is recommended at the start of hatching, 58% to 50% of digging and brought back to 60% 12 hours before the chicks come out.

III-5- Sorting, interventions and packaging

III-5-1- Sorting of chicks

After hatching, the chicks are sorted on the basis of the following criteria:

· Live weight: the chick whatever the species weighs on average 68 to 70% of the weight of the egg. Thus, the too small chicks are eliminated,

· Vigor: the chick must have good sharp eyes,

· Down: it must be dry, long, silky and homogeneous,

· Limbs: The chick has to keep on his legs color pink and shiny,

· Umbilicus: it must be well healed, cordless, dry and clean,

· Abdomen: It should be flexible and not swollen,

Malformations: the quality chick must not have malformations in the eyes, beak, legs and wings,

III-5-2- Interventions

After sorting, several operations are carried out on day-old chicks. These interventions particularly concern:

· Sexing: this operation is done for chicks of the laying type and reproduction type. We base ourselves on the eversion of the cloaca, the coloring of the plumage (reproductive) and epmlumement on the wing,

· Vaccination: mainly Marek's disease and infectious bronchitis,

· Dewinging: mainly for guinea fowl and turkeys,

· Banding: in the selection and research units,

· Décaronculage: mainly for the breeding turkey

III-5-3- Packaging

IV- HEALTH AND HYGIENE CONTROL OF THE HATCHERY

The hatchery is an ideal environment, very favorable to the development and multiplication of microbial germs (fungi, bacteria, viruses, etc.), because all the favorable conditions: temperature (12 to 38 ° C), humidity (55 to 100%) , eggs, chicks, shells, waste, dust, egg cells, boxes and chick crate, staff, machines. Indeed, the quality of the chick will depend on the sanitary conditions of the breeding and especially on the hygiene of the hatchery. Thus, it is essential that the hatchery is well designed and that strict hygiene measures are applied

IV-1 - Disinfection of eggs

The disinfection of eggs can be done before breeding breeding (the most effective) or in the hatchery upon receipt. The doses applied are of the order of 40 ml of formalin, 20 grams of potassium permanganate (KmnO4) and 40 ml of water in a m3 at a temperature of 25 to 26 ° C and a relative humidity of 80 to 85%. for 20 to 30 minutes. In incubators disinfection is prohibited between the 24th and 96th hours of incubation because it is the critical phase of incubation (installation of the central nervous system). In the hatcher, the eggs are disinfected by spraying with formalin with doses of 8ml / m3 on the first day, 13ml / m3 on the 2nd day and 22ml / m3 on the 3rd day.

IV-2 - Disinfection of rooms and machines

The incubators and hatchers are cleaned, dusted with hot water added to a detergent, then rinsing, disinfection followed by a crawl space and fumigation. Trolleys, intervention materials, and other equipment are cleaned and disinfected. Every day, the transport vehicles (eggs, personal chicks) must be systematically cleaned and disinfected both inside and outside without forgetting the cabin.

IV-3 - Staff

The first condition to impose on staff working in the hatchery is to be free from any chronic or acute illness. The hatchery staff are obliged to shower every day at each entrance and each exit. They must also wear a set reserved for this purpose .

V- CALCULATION OF TECHNICO-ECONOMIC CRITERIA

For each batch of eggs incubated and arriving at hatching, the technical and economic criteria must be calculated in order to detect anomalies and rectify the situation, if necessary. The thresholds of the criteria to be calculated are:

Non-fertile egg rate <5%

Embryonic mortality <7.3%

Non-marketable chicks <0.5%

Hatching rate> 87%

AZEROUL Embarek Engineer-teacher of the royal institute of specialized technicians in breeding Fourat- Morocco