In poultry production, incubation is the process where chicks are obtained from fertile eggs. It is a key process for the development of laying pullets and broiler chicken. There are companies dedicated to this, but producers can also implement it on their farms. The most important aspects will be reviewed in the following article.

The physiology of incubation

The egg of birds consists of an oocyte (yolk of the egg) that leaves the ovary and travels through the reproductive system. During this process, the egg acquires elements that will protect it. Two of these elements are the albumin (egg-white) and the eggshell. Finally, the bird will expel the egg through the cloaca.

When female birds coexist with males there is mating. The sperm will remain in the reproductive tract of the females. Later, this will reach the oviduct and there will enter the ovule. This fertilization will result in a fertile egg, that is, with the potential to be born a chick after incubation.

In small-scale productions, when the hens have laid fertile eggs, they are called brooders and they will carry out the incubation. Part of that process is to maintain these fertile eggs with darkness and tranquility, warmth and humidity, aeration, and care. This incubation process in laying hens lasts 21 days.

On the other hand, there are companies and farms dedicated to incubation. In this case, after the hens mate with males and lay fertile eggs, they will be transported to incubators. Incubators are specialized equipment that provides in an artificially and controlled way all the necessary care.

When it comes to incubation, the term “Hatchability” is used, which is defined as the total number of chicks that born from fertile eggs. It is an important parameter that must be constantly evaluated to monitor whether the incubation process is being successful or must be reviewed to correct failures.

Incubator

An incubator is an equipment where fertile eggs are deposited to complete their development until hatching. There are incubators where the eggs are positioned vertically or horizontally. Vertical incubators typically handle large volumes of fertile eggs and have automatically controlled environments. Horizontal incubators handle low volumes and environmental parameters are operated manually.

About the fertile egg

A high-quality selection should be made from fertile eggs. This is reflected in the good development of the chicken embryos.

For this, eggs that present these characteristics must be discarded:

• Eggs with visible dirt (feces)
• Eggs with cracked or broken shells
• Eggs whose shell presents porosity (favors the entry of microorganisms)
• Eggs with a deformed external appearance (elongated or with deformities in their shell, soft or wrinkled).

Phases before incubation

• Storage

After the hens lay the fertile eggs, they must be collected and transported to a storage room until they are sent to the incubator. The eggs should be stored at a temperature below 24 ° C (optimal between 16-17 ° C), this ensures that there is no embryonic development yet. This temperature must be set based on other factors: storage capacity, cost evaluation, insulation capacity. Proper management of the parameters must be established during incubation, avoiding evaporation and excessive condensation of the water in the egg. Otherwise, the alteration of the eggshell and the entry of microorganisms are favored. Regarding the relative humidity of egg storage, 70% is recommended.

• Preheating

After being stored, the eggs must undergo preheating. Then they are transported to incubation. In this stage, the eggs are acclimatized to avoid a sudden temperature change when going from storage (20 ° C) to incubation (37 ° C).

In preheating, the eggs should be placed at a temperature between 37-38.6 ° C for a few hours and then allowed to acclimate. Besides, humidity between 60-70%, must be maintained.

• Incubator disinfection

To ensure a controlled environment free of microorganisms, Good Hygiene Practices must be maintained. Also, it is recommended to disinfect the incubator. A protocol for the preparation, handling, application, and safety of these disinfectants should be established for the incubator.

Key incubation factors

The following parameters must be studied individually by each farm dedicated to poultry farming, taking into account its characteristics: location, altitude (AMSL), humidity, environmental temperature, economic capacity, available spaces, number of personnel, and capacity of facilities, among others.

• Temperature

Temperature is the most important and delicate factor in the incubation process. Any temperature change must be constantly monitored as its increase or decrease has serious consequences. Incubating eggs are extremely sensitive to changes in temperature. Furthermore, this parameter defines the development speed of the embryos that are incubating inside the eggs. In general, a temperature between 37 and 38 ° C is recommended. Then, the temperature must decrease during the last three days of incubation (day 18 to 21). It should be established depending on the incubator used to maintain the maximum possible hatchability.

• Humidity

Humidity is another important factor in incubation since eggs are also highly susceptible to any change in this parameter. Constant monitoring of humidity should be done and corrected as quickly as possible through the spraying of water. Occasionally disinfectants are used in this water to disinfect the eggs and to correct the humidity. The egg loses up to 10% water on day 18 as part of the incubation process. Environmental humidity also plays a role in this mechanism.

• Rotation

In natural conditions, the hens carry out the rotation of the eggs. In the incubation processes, the rotation of the eggs must be ensured depending on the day of incubation. This rotation favors the correct positioning of the embryo in the egg and prevents it from sticking. It also helps to form the internal membranes. Besides, it facilitates the arrival of heat in a uniform way to all the eggs and their entire structure.

What is Candling?

A necessary practice within the incubation is the revision of the internal state of the eggs through candling. As the word indicates, it is the observation of the egg in its internal part; light is used for this. The eggs are illuminated at one of the poles and a diagnosis is issued as observed. Candling is recommended to be done on day 7 and day 14.

This technique allows detecting:

• Eggs with dead embryos
• Cracked eggs
• Decomposed eggs: it is advisable to remove them immediately to prevent them from exploding and thus contaminating all the eggs in the batch.

Chick handling

The chicks hatch after 21 days. In farm conditions and low-scale production systems, the hen performs the entire incubation process and takes care of the newly hatched chicks. On the other hand, in medium and large-scale production systems, incubation and subsequent hatching occur under controlled conditions. After the chicks hatch, wait until their fluff is dry to change the environment. Besides, food and water should be supplied to them after hatching. Regarding the temperature, it should be between 30-32 ° C and a humidity of 70-75%, ensuring the good circulation of fresh air.

The 1-day-old chick should be sexed to identify females and males separately and give them the respective management. Chick sex can be classified by observing the cloaca with an endoscope or when it is eversioned, and thus the vestigial copulatory organ is visible. There are other methods based on the observation of the feathers and on the color genes that will give a specific phenotype, indicating the sex.

Conclusions

Incubation is a set of fundamental steps in poultry production focused on obtaining 1-day-old chicks from fertile eggs. Laying hen farms or broiler farms need this supply of chicks to carry out their respective activities. For this reason, incubation must be done carefully. For a correct incubation, a large number of factors mentioned here must be taken into account. Ensuring that all stages of incubation are in optimum operation guarantees great output of chicks born in good conditions.

References:

• Cobb (2013). Guía de manejo de la incubadora. En línea: https://cobbstorage.blob.core.windows.net/guides/26b944f0-bcb4-11e6-bd5d-55bb08833e29.pdf
• FAO (s.f.). Alojamiento y manejo de las aves de corral en los países en desarrollo. En línea: http://www.fao.org/3/a-al736s.pdf
• FIDA, (2013). La consutrcción y uso de una minincubadora con arena. Disponible en línea: https://www.ifad.org/documents/38714170/39144386/Building+and+operating+a+mini-hatchery+-+sand+method_s.pdf/c64ccda6-6084-420a-9128-357dd54be3e4
• INTA (s.f.). Cría de aves: cómo usar la incubadora familiar. En línea: https://inta.gob.ar/sites/default/files/inta_cartillas_cria_de_aves_como_usar_la_incubadora.pdf
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• Rodríguez-Moya, J., & Cruz-Bermúdez, A. I. (2017). Factores que afectan la incubabilidad de huevo fértil en aves de corral. Nutrición Animal Tropical, 11(1), 16-37.
• Ross Tech (2010). Investigación de las prácticas de incubación. Disponible en línea: http://es.aviagen.com/assets/Tech_Center/BB_Foreign_Language_Docs/Spanish_TechDocs/RossTechInvestigacindelasprcticasdeincubacinmayo2010.pdf
• Vanegas Gallego, D. A. (2014). Proceso de incubación de pollito Ross 308 en planta de incubación. Barbosa-Antioquia (OPAV) (Doctoral dissertation, Corporación Universitaria Lasallista).