The embryonic development of chickens is completely completed outside the mother's body, and the nest chickens that naturally hatch chickens turn the embryo eggs with their claws and beaks as many as 96 times a day. Physiologically speaking, the egg yolk contains more fat and has a light specific gravity, and the embryo floats on it, and if the egg is not transferred for a long time, the embryo is easy to adhesion. The purpose of the egg transfer is to change the position of the embryo, prevent adhesions, promote amniotic motility and improve amniotic blood circulation. At the same time, it also increases the contact time between the yolk blood vessels, allantoic blood vessels, egg yolk and egg white, which is conducive to the absorption of nutrients.
(1) The number of times the egg is flipped over
When the soil method is incubated, it is generally 3-4 hours to transfer the eggs once; When the incubator incubates, it is generally 1 time to turn the eggs every 1-2 hours. The hatching rates of fertile eggs were 67.4%, 70.4%, 73.4% and 78.1%, respectively, when the number of eggs was transferred 2, 4, 6 and 8 times per day, respectively. If the three-dimensional incubator used by the farmer is not hand-cranked or automatic egg turning accessories, to manually open the door incubator, the egg should be turned every 2-4 hours, and the egg should be turned 4-5 times a day, and the number of door openings should not be too much, because it will affect the stability of the temperature in the machine. If the incubator used is an automatic egg flipping machine, it is sufficient to flip the eggs once per hour.
(2) Start and stop flipped egg time
During the incubation process, the early transfer of eggs is more important than the later stage, especially in the first week of incubation. From the first day of artificial incubation until the 19th day, the eggs must be turned regularly. During the incubation period, if the eggs are not turned on the 1st to 18th day, the hatching rate is only 29%; If the eggs are turned on the 1st to 7th day, the hatching rate is 78%; If the eggs are turned on the 1st to 14th day, the hatching rate is 95%; If the eggs are turned on days 1-18, the hatchability rate is 93%.
The machine incubation method generally stops the transfer of eggs and the transfer of the tray after 18 days of incubation. If the egg flipping was stopped on the 16th day and the plate was moved, the hatching rate of the fertilized eggs was 84.77%. If the egg flipping was stopped on the 19th day and the plate was moved, the hatchability of the fertile eggs was 82.77%. There was no significant difference in hatchability between the two groups, indicating that it was feasible to stop turning eggs and move the tray on the 16th day of incubation in advance. Because after the 12th day of incubation, the self-warming ability of the chicken embryo is still very strong; After the 14th day of incubation, the embryo will be covered with feathers, and the embryo will not be transferred to the egg and will not cause the embryo to stick to the shell.
(3) Angle and method of flipping eggs
The plane incubator adopts manual egg turning, and the operation must be stable, light and slow, and the eggs must be strictly shocked. At present, the machine hatching is mostly automatic flipping eggs, and the angle of the eggs is 45 degrees in the horizontal position, and the eggs can not be only in one direction, otherwise the mortality rate of the embryo will be increased. You should press the egg turning switch button first, and after turning to one side at 45 degrees to automatically stop, then turn the egg turning switch plate to the "automatic" position, and then it will automatically turn the egg every certain amount of time in the future. When turning eggs, pay attention to the temperature, humidity and ventilation of the incubation, and give a record.