Configuring your setter temperature program
The standard Petersime OvoScan™ temperature program offers a “safe” starting point for general incubation. It achieves good hatch results with a high standard in chick quality. However, it is not the optimum profile for all flock types, ages, storage time, and many other factors that can affect embryonic development, growth and overall chick quality. Configuring the optimum temperature profile for your hatchery can only be done with site specific data analysis combined with the expertise of the Hatchery Manager/Company Incubation Specialist. However, there are some basic principles that should always be considered.
By Roger Banwell, Hatchery Development Manager
The size of the egg has an influence on its incubation behaviour. This is because the efficiency of heat exchange depends on the surface of the egg, as heat can only be exchanged at the contact surface between the shell and the surrounding air. For a small egg, the ratio of surface to volume is relatively higher than for a large egg, therefore, small eggs will lose weight more easily.
The ratio of surface to volume of an egg becomes most significant during initial egg warm up and at peak heat production.
During the initial 12 – 24 hours, the entire body of fluid contained within the egg needs to be fully warmed to incubation temperature. To achieve this, the air temperature is set at a slightly higher set point in this period. Typically, small eggs require lower temperatures and/or a shorter warm-up time than large eggs.
At peak heat production (days 16-18):
A large egg has relatively less surface area than a small egg to dissipate the embryonic heat production. Therefore, at peak production, heat damage can occur. Small eggs on the other hand risk to be overcooled, causing significant chick quality issues.
Therefore, the final average shell temperature during peak heat production is often set slightly lower than 100.0° F for older, large egged flocks. For young, small egged flocks, it can be set at a temperature greater than 100.0° F.
Fertility must always be considered during the peak heat production phase. If fertility is low, small eggs could be overcooled, while the risk of heat damage for the larger eggs diminishes.
A long egg storage lengthens the total incubation time, and these eggs are often set in earlier in order to achieve the required take-off timing. As a consequence, the point of peak heat production differs between short and long stored eggs. This does not require any changes in program configuration when using the OvoScan™ system.
However, optimal temperature conditions cannot be achieved with a wide mix of storage times within the same single-stage incubator. If small variations in egg storage times are unavoidable, it is highly recommended to take the principles of “balanced loading of the setter” into account.
Different flocks have different heat production profiles: the amount and timing of heat production differ from flock to flock. With the real-time OvoScan™ system, there is no need to adjust temperature set points according to flock type.
As with egg storage times, it is not advisable to set mixed flock types within the same single-stage incubator. If this is unavoidable, the same balanced loading approach is strongly recommended. In this case, ensure that the min/max limits of the temperature program incorporate the different heat production profiles created by the different genetics.
The same rules of thumb apply to the hatcher temperature profile. In addition, the effect of early/late transfer (see article: “Understanding the hatching egg”) and the thermal transition between the two machines should be taken into account.
Starting from the advice above, you can further optimise your temperature programs through breakout sessions and chick quality assessment. As with all aspects of optimum incubation performance, good data acquisition and analysis are essential and can be the difference between profit and loss.