Update on Incubation

The latest knowledge on incubation conditions and management were presented at a special symposium held in conjunction with the International Poultry Expo in Atlanta, Georgia, US. Jackie Linden, senior editor of ThePoultrySite, reports.
calendar icon 8 February 2012
clock icon 9 minute read

At the Hatchery and Breeder Clinic event, held in conjunction with the IPE in Atlanta in January 2012, two speakers presented updates on the conditions required for embryonic development and how to manage incubators to deliver those optimum conditions. Two of the IPE exhibitors were also invited along to present their companies' innovations in hatchery automation and heat recovery systems.

Requirements for Embryonic Development

According to Dr Mike Wineland from North Carolina State University, the most important incubation conditions are temperature, ventilation, humidity and turning and these are vital as they impact hatchability and subsequent chick development, including energy metabolism, thyroid activity, intestinal maturation, cardiac function and tendon/bone growth, among others.

"Malpositions and abnormalities are indicators of poor management," he said, "because they affect nutrient utilisation. Incubation parameters affect extra-embryonic components that help the developing embryo to utilise the nutrients in the egg." Those components include the yolk sac, amnion, allantois and chorion, he explained.

Ventilation is vital to embryo development. How well the air moves within and through the equipment depends on the machines and eggshell conductance.

Early embryonic respiration takes place in the sheet of white cells where blood vessels develop from day 2, said Dr Wineland. Later, the chorioallantois takes over as the main breathing organ for the embryo, as the blood vessels in this region are linked to the eggshell pores. It is these pores that account for the variation in moisture loss from a single flock.

Dr Wineland explained that oxygen consumption by the embryo increases sharply from day 8 of development until day 16, and this is followed by a period known as the ‘plateau stage’, after which, the embryo pips up into the air cell within the egg.

As the embryo enters the plateau stage, it continues to grow and its organs function with limited oxygen because the maximum air conductance through the pores has been reached. At this time, the embryo redirects the oxygen to the heart and brain and away from muscle development. This re-direction has an important impact of the development of late-maturing organs and tissues.

Turning is important to complete the formation of the yolk sac membranes and blood vessels, as well as to supply nutrients to the extra-embryonic organs and to remove metabolic heat, continued Dr Wineland. In multi-stage systems, turning helps to transfer heat from the older embryos to the younger ones. This requires a consistent air flow throughout the machine.

Furthermore, turning is known to affect the formation of sub-embryonic fluid. Water from the albumen moves into the yolk, causing it to split into lipid and aqueous phases, a process essential for embryonic development and impacting hatchability, particularly through early embryonic mortalities.

Dr Wineland demonstrated that turning is essential for the first 12 days of incubation, and particularly for the first week.

The angle of turning is important to prevent stratification in the yolk although his research revealed no differences in subsequent broiler performance if the angle was 35, 40 or 45°.

Relative humidity (or vapour pressure) regulates water loss from the embryo. Until day 17 or 18, the embryo is bathed in amniotic fluid and allantoic fluid, which act as a reservoir to maintain the correct body water content. Egg moisture loss is higher in multi-stage than single-stage incubators, and it is not uniform throughout the incubation period, said Dr Wineland.

Incubation temperature is important because it affects the time of hatch, he said. Using the example of turkey embryos, he showed how low temperatures early in incubation result in smaller embryos because the organs do not develop properly. Later in incubation, temperature mainly affects nutrient utilisation and organ maturation.

Excessive temperatures slow development rate. Dr Wineland showed from his own and other researchers’ work that reductions occur in the growth of the villi in the embryonic jejunum and muscle fibre development. This latter point is significant for subsequent growth of the bird as all muscle fibres are present at hatch.

Finally, Dr Wineland showed how thyroid metabolism is affected by incubation temperature. This impacts on leg health, and hence on getting the broiler to market as the thyroid gland affects both bone symmetry and tendon growth.

Incubation Needs for Modern Breeds

Today's breeds have brought about changes in incubation management, according to hatchery specialist with Cobb's World Technical Support team, Scott Martin. He gave the example of the move to single-stage incubation "because we've plateaued in what we can do with multi-stage incubation".

Improvements in feed conversion and 49–day bodyweight for modern broilers have led the European to industry there to make the move to single-stage incubation but Mr Martin said the results can be just as good from a well–managed multi–stage incubation system. The important factors are proper egg holding, managing the reduction in labour availability and timely trouble–shooting.

Regarding holding time, hatching eggs are usually stored for one ot four days at the farm, followed by up to five or even 10 days before entering the incubator. Temperature fluctuations over these periods should be avoided, said Mr Martin. He suggested using data loggers amongst the eggs in the trays to monitor the temperatures and highlight any problem areas. They are especially useful for showing trends, he said.

Today, hatcheries are achieving high performance, averaging 85 per cent in the US, for example, This has been achieved not only through advances in genetics, feeding etc. but also by increasing knowledge of the impacts of temperature on hatching eggs. The crucial factor that has emerged from research and experience is the need to maintain a constant temperature at each stage, avoiding fluctuations.

Mr Martin then turned to his recommendations for parameters to measure to maintain and even improve the results from incubation. Because it is a measure of efficiency, he suggests the percentage hatchability of fertile eggs as the key measure.

Hatchability progress requires quality assurance and standard operating procedures (SOPs) to hit their respective marks. These are vital for performance, both at hatching and for broiler performance, said Mr Martin.

Although it may be difficult to get funding for investment in, for example, the latest heating, ventilation and air conditioning (HVAC) systems when hatchability has already reached 88 per cent, such investment will soon be returned in terms of improved broiler performance, he suggested.

Ventilation equipment needs regular and correct maintenance, Mr Martin stressed, showing examples of poor maintenance at hatcheries where damage and/or debris prevents the equipment from functioning properly. Condensation traps and walls should always be cleaned and disinfected between batches, he said, and filters should be cleaned and dated so they can be replaced regularly.

All monitoring equipment in the hatchery needs to be calibrated as often as necessary. This should not be carried out every quarter, for example, if it is found to be off each time; recalibration needs to be carried out more frequently until almost no adjustment is needed. Modern room controllers are now effective, said Mr Martin, but they still require checking.

Basic checks recommended by Mr Martin to monitor settings are:

  • embryo temperatures using different methods
  • moisture loss from eggs, for example, by measuring the air cell
  • pipping, and
  • chick temperatures when they have hatched.

All these checks are aimed at confirming what you think you have, said Mr Martin said.

Checking residues at break-out will help in finding patterns of possible problems during the early (days 1 to 7), middle (days 8 to 14) or late (day 15 onwards) stages of incubation.

Candling eggs is important to assess fertility (if carried out on days 10 to 12) and on the residue at hatch. Mr Martin suggested keeping these checks as simple as possible: overall fertility and hatchability and hatch of fertile, noting also the age of the breeding flock at the time.

Chick quality should be assessed on day 1 and during the first week of life as good chicks are likely to perform well subsequently.

When the assessment of chick quality is linked up to that of the incubator, an overall picture is formed.

"Chick temperature is the best tool for management and managing wisely," Mr Martin said. He concluded: "We must get back to basics and fix what we've got" for the best possible incubation results.

New Equipment and Concepts for the Hatchery

Following the technical presentations, two companies introduced new ideas and solutions for hatcheries.

For KL Products, VP of International Sales & Marketing, Rick Bennett, explained how hatchery automation has developed over the last 30 years since his company was founded in London, Ontario, Canada. With all equipment designed and manufactured in that country, it offers automatic washing systems, food processing automation and, his focus at the conference, hatchery automation.

Mr Bennett explained that KL Products offers a range of hatchery equipment but he focused on automation in his presentation, demonstrating with videos robotic advance transfer in the egg transfer room and tray de-stacking and re-stacking in the take-off room.

Hatchery Planning Company, based in Austell, Georgia, offers complete hatchery design services for new and existing facilities. Phil Hicks, project sales manager, focused his presentation on the company's heat recovery systems, which capture wasted energy and deliver it to a device or system where that energy can be used.

Modern heat recovery systems are now very efficient, said Mr Hicks, showing a typical roof-top unit and a fluid cooler. The modified HRC is a combination of chiller and boiler, which can provide cold water to cool machinery, heating for the chicks and hot water for cleaning.

February 2012

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