13 June 2022

3 minute read

By: Martin Barten

Customers and participants on our training courses often ask me: “What is the most important aspect of incubation?” Usually, I turn the question around and ask them what they think it is. Temperature is often mentioned, as well as relative humidity and turning. Indeed, a turning failure in early incubation can seriously impede hatching.

In my mind, however, the question should be answered differently, or even asked differently, and should be: “What is the most important period of incubation?” For me, this is clearly the first ten days.

On day ten of incubation, the embryo is more or less complete and the body parts are clearly recognizable as a mini chick. All the embryo has to do from this point on is grow. Of course, the embryos must not overheat and they must receive sufficient oxygen and lose sufficient weight to achieve an air cell that can easily be pipped, but the real challenge is to get every embryo as uniformly as possible to day ten and in such a way that it is well developed and strong. After all, whatever you do wrong in this period cannot be corrected later! Getting the first ten days right is therefore the foundation for a good and uniform hatch and a narrow hatch window. Mother Nature knows this too: a broody hen is much more attentive to her nest at the start of incubation than in the last few days, when she leaves the nest more regularly for food and water.

So, how to get the first ten days right? This starts with loading the setter with eggs that are as similar as possible in terms of breeder age, preferably with no more than five to ten weeks difference. If this is not possible due to breeder flock size in relation to the setter capacity, at least use the different sections in the setter and load the setter ‘in balance’. Also, try to minimize differences in egg storage duration, as storage clearly has a delaying effect on the rate of embryo development. Next, make sure that all eggs reach incubation temperature as uniformly as possible, through proper preheating. The effect of incoming air on temperature uniformity should also be minimized by keeping the damper closed for a few days, or at least reducing the ventilation rate and ensuring that incoming air is warm and humid enough.

A mistake often made in practice is to start with an incubation temperature that is too low and/or to reduce it too quickly. When aiming for an eggshell temperature of 100°F (measured with Braun Thermoscan), the reality will be that the internal egg temperature is too low. My method, which has proven successful more than once, is to achieve an internal egg temperature of 100-100.2°F. For that, I start with a relatively high set point of 100.5°F or even a bit higher for the first 12 hours and maintain the set point for a couple of days well above 100 °F until the heat production of the embryo is higher than the cooling due to the evaporation of water through pores in the eggshell. This ensures a sound foundation on which the embryo can successfully build to become a strong and robust day-old chick.