3 things you should know about bird breeding — Part 2 Turning of the Eggs

This is the second article of our 3 part series about artificial bird incubation. You can find the first part here in case you missed it: https://medium.com/@hatchapp/3-things-you-should-know-about-bird-breeding-part-1-9ca60ba2c3db

The Turning of the Eggs

The eggs of most bird species have to be turned so that the embryo inside can develop correctly and hatch at the end of the incubation period. Eggs that are incubated by the surrounding temperature, like reptile eggs laid into the sand, don’t need any turning. Turning those eggs may kill the embryo.

At the beginning of the incubation period, when the development of the blood vessels starts inside the egg and the embryo becomes visible for the first time, the regular and correct turning of the eggs is very important. At this time the very mobile embryo always floats to the highest point inside the egg. Without turning, the embryo may adhere to the egg skin. In that case, further development of the chick inside the egg as well as hatching may be negatively influenced. One result of a chick sticking to the inner side of the egg shell may be inability to retract its yolk sac just before hatching.

There are different methods for turning eggs. The two most common methods are the rotation around its longitudinal axis or to the tilting over its pointed end. The eggs can either be turned non-stop as it is often done when they are tilted over the pointed end or the turning may be interrupted by breaks as it is often done when the eggs are rotated around their longitudinal axis. When they are rotated around the axis, it´s very important that, when looked at from one end, the eggs are alternately turned 180° clockwise and then, when turned the next time, 180° counter clockwise. It is, therefore, of great help to mark the eggs (when placed flat on a table) on top with a “+” and underneath with a “-“. When the eggs are turned by hand and a “+” is visible on top, then the egg has to be turned clockwise. If a “-“ is seen on top, then the egg has to be turned counter clockwise. If the eggs are turned automatically inside the incubator, then the “+” and “-“are a good control that the turning mechanism works well. It is important that after each turning inside the incubator, all eggs either show the “+” or the “-“on top of the egg. If this is not the case then the eggs have to be turned by hand accordingly multiple times a day. After each procedure, all eggs should show either a “+” or a “-“on top.

If the eggs without any previous natural incubation are collected, they must be stored at a cool temperature and turned multiple times a day before being placed in the incubator. Small numbers of eggs can be turned by hand, large numbers with an automatic turning mechanism. There’s quite a bit of conjecture about the best storage temperature, but it’s common knowledge that the embryo starts to develop when the temperature is too high. This premature development could cause them die shortly thereafter, and when the real incubation at 37.5°C starts, it’s too late for them. I have good hatch rates when I store the eggs of my falcons at about 10 to 13°C, turn them minimum 6 times a day by hand and put them within 2–3 days into the incubator to start incubation. Needless to say, eggs that already have natural incubation by the parents must go straight in the incubator before they cool down.

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