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Enhancing hatch and post-hatch performance with the non-linear weight loss approach

Want to obtain maximum hatchability and chick quality with more accuracy and less labour? Petersime took this question to heart and conducted extensive research on how to obtain optimal hatch and post-hatch performance. 

by Roger Banwell, Petersime Hatchery Development Manager

The findings? Environmental conditions play an important role in influencing hatch rates and chick quality. By optimising these factors, you can dramatically boost performance and yield better results. Roger Banwell, Hatchery Development Manager at Petersime, explains how the company’s weight loss system fits this philosophy.

“One of the key issues during the incubation period (i.e. the time it takes an embryo to grow into a chick) is egg weight loss. Before a chick can break out of its shell, it needs to pierce an air cell inside the egg so it can acclimatize its lungs to the outside atmosphere (internal pipping). This air cell can only be formed if the egg loses 11-14% of its weight in the form of water vapour.”

Optimising this weight loss can be quite a challenge. That’s why Petersime came up with its Dynamic Weight Loss System™ (DWLS™). “Traditionally, hatchery managers have used linear weight loss systems, which gradually and steadily allow the egg to lose fluid during the incubation process. However, our research showed that we got better results when we followed a non-linear trajectory and maintained high fluid levels during the initial stages of incubation. We then removed the fluid once the embryos were fully developed. DWLS™ measured egg weight at regular intervals and automatically adjusted the incubation environment, resulting in optimal weight loss.”

Comparing weight loss systems

Petersime conducted extensive trials to test its weight loss system. “We ran 12 field tests comparing the two weight loss methods, linear vs non-linear (i.e. DWLS™), on roughly 1,380,000 eggs from two breeds or ‘flocks’ (Ross and Cobb). The egg-laying birds were divided into three age groups: 28-36 weeks, 37-45 weeks and 46-54 weeks.”

Scheme of the applied methodology

The researchers applied the following methodology: “We programmed two identical single-stage setters (cf. inset) with the exact same climatic conditions to achieve different types of weight loss. This meant that an egg on a linear trajectory lost more weight on, say, day 9, than an egg in a non-linear incubator. However, by the time the eggs were ready to be transferred to hatchers, all of them had lost the same amount of weight. We used identical hatchers and subjected the eggs to the exact same conditions. Once hatched, the chicks were moved to separate houses, where their progress was further monitored. Between field tests, we alternated weight loss methods between the setters. This way, we were able to rule out any external or mechanical influences.”

Constant interaction

The main challenge for Petersime was to identify the ideal conditions inside the setter. No easy feat considering the differences in geographic location, parent flock feed and egg-laying conditions. “What works in Russia does not necessarily work in South Africa or Indonesia. You have to find the optimal conditions for each location. After all, you want maximum hatchability and optimal development, as well as better chick uniformity and consistent results. Ideally, all of your birds should reach the same weight at the same time, not just some of them.”

Non Linear Weight Loss vs. Linear Weight Loss

This is where Petersime’s BioStreamer™ concept and Embryo-Response Incubation™ process come into play. “The idea is to continually monitor embryo behaviour and interactively adapt the incubation conditions according to their specific needs. No two batches of hatching eggs are alike, so you need to be able to customise their environment. Traditional single-stage incubation systems ignore this and just use averaged incubation parameters.” With Petersime technologies, hatchery managers gain better insight into the incubation process. “We make it easier for them to identify the ideal incubation conditions for their setters. In addition, our experts are always on hand to provide professional training and advice.”

Improved performance

But does this non-linear weight loss method actually enhance performance? Petersime is convinced that it does. “Our trials show a definite improvement in both hatch and post-hatch performance. On average, we got +0.91% more chicks to hatch, which means that fewer died inside the egg during the final incubation stages (so-called ‘late deaths’).”

Hatch results of the trials

Once hatched, the chicks from the non-linear weight loss setter were also more robust. “We observed lower mortality rates, with -0.23% fewer chicks dying after hatching. We also had heavier grow-out weights, with our ‘non-linear’ chicks weighing up to 72 grams more than the ‘linear’ ones. With each trial, we noticed the same measurable performance advantage. ‘Non-linear’ chicks developed more slowly during the initial stages, followed by a period of compensatory growth. In other words, they quickly caught up with the ‘linear’ chicks and ultimately surpassed them.”

Weight Loss per age group

What else did Petersime learn from its trials?

Some of the restrictions of traditional incubation have clearly limited both our actions and our thinking. Whilst we don’t claim to have changed the laws of avian science, we now know that optimum weight loss is at point of hatch. With improved uniformity, we can run the hatchers with low humidity levels until the hatch is complete and our approach to weight loss at transfer can be far more flexible.

Ventilation-Weight Loss up to Point of Hatch

The non-linear approach and a better understanding of the target weight loss enables a far greater degree of control in ventilation. This improves temperature uniformity, energy efficiency and accurate/flexible gas exchange control which allows improved vascular development. The end result is a better hatchability, improved chick quality, optimum post-hatch performance and of course a more natural incubation process that offers improved welfare conditions.

Single-stage or multi-stage setter?

Hatchery managers have traditionally used multi-stage setters for incubation. This involves putting eggs of several embryonic stages in one single incubator, hence the name. As Roger Banwell explains, “This means that all eggs are subject to exactly the same conditions, regardless of what stage of the process they are at. If you get good results, you are unable to pinpoint why. As a result, it’s impossible to replicate your success.”

Eggs at different stages require different environmental conditions. “This is why we also offer single-stage setters. All eggs go in and out of the incubator at the same time. You get complete and consistent control over every parameter inside the setter. The result? Better performance at each stage of the process.”