Temperature control in poultry incubation

When incubating poultry, the hatching eggs quality is the intrinsic factory and the incubation temperature is the main external factory. Only quality fertile eggs can give birth to healthy poult. But without appropriate temperature, even high quality fertile eggs could not lead to high hatchability and premium Poult.

The temperature set is highly related to the kind of the poultry, size of the eggs, incubator type and incubation season. The poultry embryos are adaptive to the ambient temperature to some degree and will have chance to hatch under temperature of 35~40.5℃. But the embryos are very sensitive to temperature above 40.5℃ or below 35℃, and the embryos will die massively under such abnormal temperature for more than 3 hours. 

Know-how in controlling incubation temperature

1. The difference between egg temperature and the incubator temperature. Egg temperature is the temperature measured on the surface of the egg, while the incubator temperature is the air temperature in the incubator. Currently, there are two methods to measure the temperature, to measure the egg temperature or to measure the incubator temperature.

2. Method to measure the incubator room temperature. In the old egg incubators, most of the temperature sensors are fixed onto the incubator and was able to measure the room temperature in the machine. But in actual practice, the egg temperature is usually different from the machine egg incubator temperature. At the incubation beginning, the hatching eggs don't set free heat. In order to get 38℃ on the eggs, the room temperature in the incubator should reach 39 ℃. With the embryo age increasing, the embryo develops its own body temperature, so the room temperature in the incubator will have be to lowered keep the egg temperature stable at 38℃. In the late stage of the incubation, the room temperature in the egg incubator should be turned down to 37℃, so as to keep the egg temperature stable at 38℃. Therefore, when using this kind of incubator, the room temperature of the incubator should be frequently set to satisfy temperature requirement for incubation. Moreover, the temperature evenness and the ventilating fan speed are quite different, so the incubation technician should be not only experienced in incubation, but should be also experienced in using a specific model of incubator. The temperature instructed in incubators user manuals are specially advised according to the characteristics of the machine. Usually, it should be first high, then medium and then low in the late stage of incubation.

3. Methods to measure egg temperature. This method is a newly invented measuring method these years. The temperature sensor is in touch with the egg surface. During incubation, the incubation workers will only set the required temperature and the egg incubator will automatically adjust the incubation temperature, according to the egg temperature reactions. Even inexperienced workers can perform the job well. When using this kind of egg incubator, the technician can measure the temperature on several eggs and the se the temperature sensor on the egg with the medium value. Every 3-5 days, candle the eggs around the temperature sensor, so as to assure that there are no dead embryos and exact embryonic development with other eggs.

4. Adjust the temperature according to eggs candling. Incubation technician may regularly take some eggs at random for candling and compare the embryo through candling with the standard egg candling map, so as to adjust the temperature accordingly. When the temperature is low, the embryonic development is slow, vice versa. After times of candling and comparison, the technician will be able to formulate a suitable temperature solution. When incubating eggs, the candling map is different from day to day, but the difference is quite slight. Therefore, it is advised to specially pay attention to three phases.

(1). Black eye period. When the chicken eggs are in the 5th day of the incubation process, duck eggs 6th day, goose egg 7th day of the incubation process, randomly select 20 eggs, place the eggs horizontally for 5 minutes and then candle the eggs. If it is well developed, a black spot could be seen. When black spot can be seen in most of the eggs, it indicates that the temperature has been properly set. If black spot appear only in few eggs, it indicates that the egg is still on the 4th day of the incubation process, due to low temperature. In this case, the temperature should be increased by 0.2-0.5℃. If black spots could be seen in all the eggs, it means that the eggs are on the sixth day of the incubation process, due to high temperature. In this case, the temperature should be reduced by 0.2-0.5℃.

(2). Blood vessels connecting period. When the chicken eggs have been incubated for 5 days, duck eggs for 6 days, goose eggs for 7 days, the blood vessels of well-developed egg spread and become connected. If the blood vessels in most of the eggs become connected, it indicates that the temperature has been properly set. If the blood vessels on more than 30% of the eggs are still not connected, it indicates that the temperature is a little low and it needs increasing by 0.2-0.5℃. Vice versa. In this phase, it should be noted that excessive temperature can also influence the blood vessels’ connection.

(3) The bright part darkening period. When chicken eggs incubated for 17 days, duck eggs 21 days, goose eggs 23 days, the small end of the egg becomes dard and the bright part is no longer seen. If more than 70% of eggs show this phenomenon, it indicates that the temperature has been properly set. If more than 30% of the eggs don't show this phenomenon, it indicates that the temperature is too low, and should be increased by 0.2-0.5℃. Vice versa.