Managing the hatch window
During a long intercontinental flight recently, I found myself thinking back on one of the first visits I ever made to a customer hatchery for Pas Reform toward the end of 2003. I had just accepted my new position, and the visit was at a client’s hatchery in Asia where they had very recently made the change from multi-stage to single-stage incubation.
By Martin ‘Tiny’ Barten, Senior hatchery specialist, Pas Reform (Barten@pasreform.com)
Upon arrival I received an enthusiastic welcome. The hatchery had already processed several hatches with their new single-stage equipment, and I was told by one person that hatchability had increased 5%, with another person citing an increase of as much as 7%. Everyone seemed very pleased with the quality of the chicks, having previously found substantial variations ranging from dehydrated chicks with long wing feathers, to chicks still wet at the moment of pulling. After the switch to single-stage incubation, they found the chicks much more uniform in appearance. In those days, the term “hatch window” was not widely used. Today, we would describe their observations as the result of a reduced hatch window.
Single-stage vs multi-stage
When asked if they knew how many hours before chick take-off the first chicks usually hatched using multi-stage incubation, I was advised that relative humidity in the hatcher spontaneously rose above the fixed set point of 53% around 4.00 – 6.00 pm, two days before chick take-off, which was routinely started at 6.00 am At the point of chick take-off, some chicks were usually still freeing themselves of their shell, while others were still quite wet. However, the hatchery could not afford to wait any longer to pull the hatched chicks, as this would cause too much dehydration in those that hatched first. I calculated a hatch window of around36 hours and over, based on these observations.
However, with single-stage incubation, relative humidity increased spontaneously around midnight, 6-8 hours later than before, and at chick take-off, virtually all the chicks were dry, with no signs of dehydration. This indicated a hatch window of approx. 24 hours, taking into consideration an allowance of 6-8 hours for just-hatched chicks to dry.
Uniformity a prerequisite
A few years later – and based on the hatchery’s earlier experience and results with single-stage incubation – the same integration opened another hatchery with new generation modular single-stage machines. Here I met a very serious, relatively inexperienced young hatchery manager, who was eager for tips to achieve good results. Our agent and I agreed to invest some extra time in training him, giving him detailed, step-by-step instructions from which he made careful notes. My first advice to him was that he should not focus solely on high hatchability, but also on achieving uniform batches of high quality, day-old-chicks – as uniformity is a prerequisite for optimal management in the broiler farms.
In order to achieve uniform batches, I suggested he set eggs with as similar a background as possible. Combining short-stored eggs and long-stored eggs, or eggs from both young and old breeder flocks together, will lead to greater variation in the chicks hatching from these eggs. He asked me how much difference in storage time and breeder flock age was acceptable, to which I replied 3-4 days and five weeks, respectively, for the period in the setter. However, during transfer to the hatcher he should try to keep the batches of eggs separated as much as possible. When the batches of eggs set in one setter differed too much in background, he could, I explained, select different temperature set points per section to gain back some of the lost uniformity. I also explained that preheating the eggs in the setter prior to incubation, e.g. five hours at 77ºF (25ºC), would help to start the incubation process for all embryos more equally, which would ultimately lead to a shorter hatch window. There was no need to explain the importance of uniform temperature distribution, as this had been an important deciding factor in choosing the supplier of equipment for this new hatchery.
Bodyweights above target
We agreed that the hatchery manager would update our agent regularly with the results he achieved – and through him I would be informed. In this way, the hatchery manager could also ask questions as they arose. According to the information I received, this hatchery manager regularly achieved a hatch window of 12-18 hours. The management of the integration praised their young manager for the good, uniform chick quality he delivered from this hatchery. Their chicks made a very good start in the broiler farms, with 7-day bodyweights typically way above target. This translated into an improved feed conversion ratio of 4 points, which in a setter of 115,200 egg places (17 cycles/year), with 85% hatchability, 95% liveability and a delivery weight of 2.2 kg, equals 139,164 kg of feed saved per year.
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