Juan Carlos López

Juan Carlos López

Médico veterinario zootecnista por la Universidad de Tolima

Diamond V

Content available in: Español (Spanish)

During our visits to hatcheries, the staff who work there frequently asked very interesting questions, which we would like to share with our readers.

What happens if the incubation temperature is excessively low in the first days?

Very early embryonic mortality will increase and the quality of the chicks will be compromised, since at the time of processing we will notice a large amount of open/poorly healed navels (Photo 1).

If the temperature is very high, especially in the first week, you can see exposed brains (Photo 2).


Photo 1. An open and poorly healed navel.


Photo 2. Brain exposed due to very high temperatures

What is the benefit of moving birds to farms the day they are hatched?

1. We must take into account that, each hour a chick goes without feed is translated to a 0.2-0.4% body weight loss.

2. We must emphasize that when the chicks are hatched, they do not yet possess fully developed physiological systems, including the digestive and the immune systems.

The digestive system requires carbohydrates to activate its development. Studies report that birds that eat early have a higher body weight at 7 days and a higher proportion of breast muscle than those that were fasted.

From an immunological point of view, food intake stimulates intestinal peristalsis and, therefore, faster absorption of the yolk with the benefits that this mainly involves the passage of maternal immunoglobulins to the circulatory systems and tissues of birds.

The delay of feed intake causes those immunoglobulins to be used as an energy source and diminish their protective functions.

Additionally, the stress of fasting produces glucocorticoids which have an immunosuppressive effect.

incubation Finally, the use of the yolk makes the claim for reduced umbilical problems at the hatchery.

Photo 3. Chicks that easily come out of its shell, with no adhesion, but will lack drying time and eventually get discarded during sexing.

Why do eggs stored for several days require more incubation time?

One of the reasons is that after reaching the physiological zero, stored eggs take longer to begin cell multiplication and the initial metabolic rate of embryonic development is slower.

Additionally, there is a prolonged internal pipping due to the increase in corticosterone levels and the partial pressure of carbon dioxide, as well as a reduction of partial pressure of oxygen in the air chamber (Photo 3).

What levels of carbon dioxide are frequently found in single-stage and multi-stage incubators? And in the hatchers?

Single stage

In single stage, after the first week we find carbon dioxide levels of 3000-4000 ppm.

Multiple stage

In multiple stage, due to its lower cooling capacity, lower ventilation is required, so we observe around 1500 ppm.


In hatchers it is common to find up to 4000-6000 ppm.

Some hatchers try to stimulate hatching of birds with high levels of carbon dioxide and can achieve levels of up to 8000-10000 ppm , with no observable negative effects.

Some hatcheries increase carbon dioxide levels by up to 8000 ppm for a couple of days, then drop to levels close to 1500 before the transfer date.

Why is it difficult to hatch eggs at higher altitudes above sea level?

At high altitude the barometric pressure decreases.

The diffusion of oxygen, carbon dioxide and water molecules increases through the pores of the shell, generating greater weight loss (easily over 15%) and less oxygen availability.

This great loss of humidity will generate mortality, and is the main challenge to face.

Controlling this notorious loss of humidity is not so easy as it is necessary for the air entering the machine to be more humid and remain inside.

In order for the humidity to remain high inside the machine, ventilation or air exchange must be lighter, but doing this can have the negative consequence that the quantity of oxygen supplied is not adequate, causing the embryonic temperature to rise to dangerous levels, lowering their viability.

Some companies that have hatcheries at high altitudes establish their breeding farms at even higher heights. Eggs from farms located at high altitudes are reported to have lower shell porosity and lose less weight during incubation.

Adding oxygen to incubators and hatchers may help decrease loss in hatch, but it is expensive and is a potential fire hazard.

What is the cause of hatched chicks with short, dry feathers and closed eyes, or birds with shells or attached membranes?

Basically at high temperature and / or low humidity in hatchers and / or excessive ventilation.

Photo 4. Hatcher door with excess fluff due to over-circulation of air.


photo 5. Birds with membranes attached as a result of high temperature and low humidity.


Photo 6. Short feathering.

What causes blood stained eggs left in trays?

This is usually due to high temperature in hatchers, which prevents the correct healing of the navels of the birds and the lesions get in contact with the eggs, leaving blood traces.

Why is there higher mortality in the first few days at the farm in chicks coming from younger breeders?

One cause is variability in the embryonic development stage of young flocks at lay, commonly generating a wider hatch window: birds that hatch first have to wait inside the hatcher trays while waiting for the other to be ready, resulting in their dehydration.

Additionally, the shells are much thicker and making egg moisture loss more difficult, generating difficulty and fatigue for the birds to pip out of their shells.

Another cause is that the thermoregulatory system is less developed, the chicks when they arrive at the farm have more problems to achieve thermal homeostasis. If the birds are cold they will not move to look for food.

Finally, the body of the young breeders is still in formation and some nutrients that the embryo requires due to the physiological demands of the birds may be compromised.

Why can there be more females than males at hatch in a broiler breeder hatchery?

This situation can be attributed to a high incubation temperature: the male embryo suffers more from heat stress since it itself generates more metabolic heat, leading to late mortality.

Additionally, due to the higher metabolic temperature, males tend to hatch first and have to wait inside the machines longer, consequently getting dehydrated and then discarded.

Finally, the high temperature generates more to-be-culled males due to problems with legs injuries and black navels.

Can the lack of turning of an incubator machine in the first days generate embryonic mortality?

Yes, due to:

  • A decrease in the vascular area of the sub-embryonic fluid.
  • A poor development of the chorioallantoic membrane.
  • Adhesion of the allantois to the yolk membrane OR
  • Adhesion of the yolk membrane to the inner shell membrane.

If there is a complete lack of turning, a significant increase in mortality will be observed in the first days of development.

When it is a partial turning (15° angle), mortality occurs in the intermediate-late stage (11-21 days).

In the wild birds turn eggs up to 96 times a day. The best hatchabilities are observed at angles of 45 to 70°. From the second week on, turning is not essential, therefore, an early transfer can be made.




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