Eggshell temperature: achieving an optimal synergy between setter and hatcher for improved chick quality

• If, however, the embryo temperature and thus the metabolic rate is exactly right, the chicks will be perfectly developed.

In commercial incubation, the temperature of the eggshell is used as an indicator of embryo temperature. The consensus is that the optimum eggshell temperature during the setting phase is around 100°F (37.8°C). Eggshell temperature control in the setter has therefore become common practice to achieve optimal results.

• For instance, Petersime’s OvoScan™-controlled setters use infrared temperature measurement technology to automatically adapt the machine’s air temperature in response to the actual eggshell temperature.

However, research indicates that adjusting the eggshell temperature right after transfer and during the hatching phase also significantly impacts hatch results, particularly the quality of day-old chicks.

WHY OPTIMIZE THE HATCHER STARTING TEMPERATURE AFTER TRANSFER?

Usually between days 16 and 18 of incubation, the chick embryo enters a stage of preparing itself for the hatching phase, and a plateau phase in embryonic heat production is observed (see graph).

At around this time, the egg transfer from setter to hatcher takes place. Ideally, transfer is organized at day 18. Still, for logistical reasons, the moment of transfer can vary between day 15 at the very earliest until day 19 at the very latest.

• As can be seen from the graph, transferring at e.g. day 16 requires significantly different conditions in the hatcher compared to transferring at day 18.

Hence, it is recommended to adjust the starting temperature in the hatcher according to the timing of transfer, considering the needs of the embryos.

A correct starting temperature ensures a smooth thermal transition from setter to hatcher, preventing thermal shocks that cause issues with vascular and yolk sac retraction, which ultimately affects chick quality.

• The graph displays the amount of metabolic heat broiler chick embryos produce over time.

WHY ADJUST THE HATCHER TEMPERATURE DURING THE HATCHING PHASE?

As hatch time approaches, the chick embryo manoeuvres into the correct position, a process that requires a significant amount of energy.

• As with all aspects of effective incubation, the key is to ensure that the ambient conditions support the chick in smoothly completing the challenging hatching process, rather than the chick hatching despite the conditions.

For this reason, monitoring and adjusting the actual eggshell temperature in the hatcher is extremely important. A hatcher temperature profile based on air temperature setpoints will never fully optimize the conditions for each specific batch of eggs as no two batches are identical.

• Variables such as specific breed, strain, flock type, egg age, etc. impact the timing and course of the temperature curve:

Research investigating the effect of temperature on layers revealed that starting the incubation with a slightly higher eggshell temperature than 100°F and raising the eggshell temperature during the exothermic phase improves navel quality.

To enable the continuation of this process, it is critical to ensure a smooth transition from setter to hatcher based on the actual eggshell temperature, and to subsequently lower the eggshell temperature to facilitate the hatching process – as illustrated in the graph.

• In high yield broiler strains, the reverse is observed. Research showed that setter eggshell temperatures between 99.4°F and 100°F yield the best results, while post-transfer eggshell temperatures exceeding 100°F negatively affect navel quality.

Ensuring the continuity of proper eggshell temperature control in the hatcher is crucial to avoid high temperatures that speed up the hatching process, ensuring there is adequate time for proper yolk absorption and for the navel
to heal correctly.

• A good-quality navel is closed, dry and free of eggshell and membrane residues. A poor-quality navel is a potential place for bacteria to enter the most sensitive part of the body cavity, which drastically increases susceptibility to diseases and the risk of post-hatch mortality.

IN SUMMARY

In nature, the concept of ‘setter’ and ‘hatcher’ doesn’t exist. The mother hen, with her innate wisdom, seamlessly transitions through the stages of incubation, creating ideal conditions for her embryos and chicks.

• In commercial incubation, the best guidance is, therefore, to look at nature and replicate the conditions experienced in the nest.

That explains why a smooth thermal transition between setter and hatcher, along with continuous fine-tuning of the eggshell temperature throughout the entire setter-to-hatcher cycle, delivers the best hatch results − listening to the needs of the embryos and new-born chicks and responding as a mother hen would.

Up to this point, configuring the optimum starting temperature and temperature profile for hatchers has relied on the expertise and experience of hatchery managers.

With Petersime’s new HatchScan™ technology, an extension of the Embryo-Response Incubation™ series, the hatcher air temperature is automatically and continuously adjusted to the needs of each specific batch of hatching eggs.