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Incubation
Pre-storage incubation: a matter of routine?
- Written by Marleen Boerjan
The care of hatching eggs during storage – at the farm, in transit or at the hatchery - is an important aspect of hatchery management that aims to preserve the vitality of the embryo.
Incubation at high altitudes
- Written by Gerd de Lange
The effects of hatching at high altitude on hatchability and chick quality depend largely on the altitude at which the hatching eggs are produced - and how the hatchery manager adjusts the incubation programme.
The effects of setting eggs small end up
- Written by Marleen Boerjan
Eggs are incubated in setter trays for most of the incubation period. Three days before hatch, the eggs are transferred to hatcher baskets. In the setter trays the eggs are placed vertically with the air cell (large end) up, while the eggs lie horizontally during hatching.
Relevance of turning
- Written by Gerd de Lange
Broody hens provide optimum conditions for embryos developing in the eggs they are sitting on. The brood patch provides heat from one direction only, and the eggs at the side of the patch are cooler than those in the middle of the nest. However, because the broody hen regularly turns and moves the eggs in the nest, uniform egg temperature is achieved.
The benefits of single-stage incubation to food safety
- Written by Marleen Boerjan
Typically, papers on single-stage incubation focus on the benefits of all-in-all-out incubator management from the points of hatchability (number of chicks) and uniformity (chick quality). Much less is written about the positive impact of single-stage incubation management on hatchery hygiene. Yet when food safety is such a pivotal issue for the modern hatchery, from tracking and tracing to physical hygiene and biosecurity measures, this is a major benefit that should not be overlooked.
Read more: The benefits of single-stage incubation to food safety
Optimal weight loss profile during incubation
- Written by Marleen Boerjan
Good hatchability is dependent on meeting all crucial incubation parameters. One of these important parameters is weight loss. Eggs should lose 11-13 per cent of initial weight during the first 18 days of incubation.
Pre-heating - an effective tool for chick uniformity
- Written by Marleen Boerjan
Modern poultry management for meat production aims to deliver uniform birds to the slaughterhouse. Hatchery practice plays an important role, because success at farm level is greatly enhanced by the receipt of chicks with uniform growth potential.
Read more: Pre-heating - an effective tool for chick uniformity
Creating the ideal hatching climate
- Written by Marleen Boerjan
The transfer of eggs from setter trays to hatcher baskets is routine in the hatchery, while the embryo continues to develop. In the final days of incubation, the embryo prepares for hatching and while embryonic growth slows down at this stage, the maturation of most of the organs continues.
Finding optimum incubation temperature
- Written by Marleen Boerjan
When a hatchery manager talks about incubation temperature, he or she refers to the temperature set point at the controller of the incubator. This temperature set point regulates the temperature of the air stream along the incubator’s temperature sensors. If the air temperature is too high or too low, the incubator controller adjusts the cooling or heating rates respectively, until temperature set point is reached.
Incubation times in the modern hatchery
- Written by Marleen Boerjan
The chicken embryo generally needs 21 days (504 h) to complete incubation, including the drying of down (Etches, 1996). In practice however, incubation periods vary considerably, as observed by Laughlin (2007) in large scale field surveys, which recorded pulling times from the setting of eggs of 500 up to 526 hours (figure 1).
Adjusting ventilation
- Written by Marleen Boerjan
Reducing ventilation at the start of incubation generally avoids the inlet of cold air. Because moisture is trapped in the closed incubator, the humidifier cold spot is also absent. Consequently closing the valves during the first days improves temperature homogeneity and heat transfer to the eggs, producing a good, uniform environment for continuing embryonic development – and an ideal start for achieving a narrow hatch window.
Managing the hatch window
- Written by Gerd de Lange
The term ‘hatch window’ is used to describe the time span between the hatching of the first and the last chick in one particular hatcher. However in practice, because it is impossible to look inside each and every hatcher basket without compromising the hatcher climate, the hatch window is estimated rather than measured precisely.
Managing incubation temperature
- Written by Marleen Boerjan
As a breeder flock ages, the number of 'clear' (infertile) eggs increases as a result of decreased fertility and increased early mortality. Consequently, with higher numbers of clear eggs, a higher proportion of the heat produced by developing embryos in the fertile eggs is absorbed by the 'cold' clear eggs placed around them.
Empty shells - a valuable source of information
- Written by Gerd de Lange
On hatch day, unhatched eggs, dead and culled chicks and empty shells are inevitably produced as hatchery waste. It is generally accepted that unhatched eggs and dead or culled chicks can be used to evaluate the incubation process, to help determine where improvements can be made. Empty egg shells are usually overlooked. But these also form a valuable source of information for the hatchery.
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