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Reduce your hatch window with these 3 recommendations

Improving the hatch window is crucial to achieve better day-old chick uniformity, higher quality and better post-hatch performance. In this article, we have gathered three key advices based on studying the behaviour of the brooding hen that can shorten the hatch window and improve the performance of your chicks.

By Eduardo Romanini, incubation research coordinator

1. Restoration of eggs

Storing eggs for longer than 7 days leads to a decrease in hatchability. In fact, the longer you store eggs, the higher the losses in hatchability will be. Stored eggs will have a higher rate of embryonic mortality between days 1 and 3 of incubation and need more hours to complete the incubation cycle time. When this happens, a number of live chicks are rejected at take-off because they hatched too late to be usable. Or the late-hatched chicks are not yet mature enough to go to the farms and will have difficulties to survive or grow optimally. The wider the hatch window, the greater the problem. Even when eggs are stored for shorter periods of time, they might have been subjected to different conditions at the farm, or they might have been mixed with other flock eggs to completely load the machines.

To narrow the hatch window, you should bring the long-stored eggs to a more uniform stage of early embryonic development before incubation starts. Also when eggs are being stored for a short time, restoring them is beneficial as their variability will be reduced. There is an enormous potential in restoring the hatchability of stored eggs, and even improving day-old chick uniformity, with heat treatment before incubation. It is crucial, however, to accurately control the key incubation parameters. To achieve a consistent successful outcome, you must precisely measure and control the egg shell temperature in the incubator and regulate the warm-up and cool-down phases of the eggs.

2. Thermally balanced loading

Batch mixing is quite common in modern and large-scale incubators. However, you need to load the machines in a pattern that looks for maximum balance and uniformity. Understanding the airflow distribution in the incubators is crucial to achieve more thermal uniformity and a reduced hatch window.

In short, it is best practice to load the incubators according to the airflow distribution in combination with the metabolic heat production of the embryos. For example, for a machine configuration with central mixing fan and cooling/heating elements, put the batches with higher fertility or bigger eggs (those that produce more heat) in the position closest to the pulsator for better heat dissipation. Trolleys with eggs with lower heat production (e.g. with lower fertility) should be put in the middle of the incubator, while the eggs with intermediate heat production should go near the incubator walls. The consequences of a thermally unbalanced machine are greater variation and a wider hatch window.

Not only during the first 18 days of incubation, but also during the hatching phase should you pay attention to thermal balance. It is extremely important to take metabolic heat production into account when transferring the trolleys and positioning them in the hatcher.

You can learn more about this topic in our series on ‘thermally balanced loading’, or if you are a member of the Operational Excellence Programme™, feel free to also watch the webinar on thermal balancing.

3. Active embryo/environment interaction during hatching

Ideally, you would transfer eggs from the incubator to the hatcher at around 18 days. For some reason, however, it might be necessary to carry transfer at another time; hence, the embryo may have moved to a different stage of development, meaning the eggs may need precisely adjusted conditions to progress towards hatch (Figure). In the following graph, you can see how the temperature of the embryo evolves through the various stages of the incubation process: vascular activity (blood that flows in the outer membrane) (1), chicken positioning (2), internal pecking (3) and external pecking (4):

For example, depending on the time of transfer, you will need to set another air temperature in the hatcher. To start the hatching phase under the best conditions, it is equally important to identify the periods in which the embryo is very responsive to environmental stimulus (Figure). Synchro-Hatch™ will do the triggering of temperature and CO₂ stimuli for you, by detecting the right biological moment to support the embryos in the last steps before they hatch. The following simplified graph shows the main interaction possibilities between environment and embryo:

For example, when the embryo is in an energy-saving period, air temperature should be reduced accordingly. Similarly, the CO₂ levels applied on the correct period and magnitude will not cause any damage, but will trigger the embryo to respond naturally to internal and external pipping.

Members of our Operational Excellence Programme™ can also watch a step-by-step video on how to adapt their incubation programme on our dedicated service website.

With good hatchery management and proper control over these three key elements that influence the incubation and hatching process, you can reduce your hatch window and maximise your profit.

To summarise:

  1. Restoration of eggs during storage: bring embryos to a more uniform stage of development before incubation starts
  2. Thermally balanced loading: take the advantage of knowing the airflow in the machines and use it to minimise the existing differences in heat production among mixed flocks
  3. Embryo/environment interaction during hatch: monitor the right biological moment to support embryos with positive stimuli of temperature and CO₂ during hatch