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The non-linear weight loss approach

The non-linear weight loss approach

by Roger Banwell, Petersime Hatchery Development Manager

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. 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.”


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.” ...

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