Effects of incubation conditions on hatching rate and quality of chicks

Incubation of eggs is an important part of chicken production. The hatching rate directly affects the economic benefits of chicken production. In order to obtain ideal hatching rates and quality chicks, hatching conditions are a key measure in addition to cultivating healthy and productive chicken breeds, improving the quality of eggs and enhancing the disinfection of eggs. In this paper, the effects of incubation conditions on hatching rate and quality of chicks were discussed from the aspects of temperature, humidity, ventilation, egg turning and cool eggs, and ways to improve hatching rate and quality of chicks were discussed.

Temperature

1.1 The role of temperature

Temperature is the most important condition in hatching and plays a decisive role in hatching rate and health rate. Because various metabolic activities during embryonic development are carried out under certain temperature conditions. Without proper temperature, the embryo cannot develop or develop abnormally, and there is no good hatching effect.

1.2 Temperature requirements

In the early stage of incubation, embryonic material metabolism is in the primary stage, lacking self-temperature regulation ability, so higher temperature is needed. In the middle of hatching, embryo metabolism is increasingly strengthened, and body temperature regulation ability is gradually strengthened. At this time, temperature should be kept stable; Before the shell, the embryo has the ability to regulate body temperature, plus its own metabolism is strong, producing a lot of body heat, at this time the temperature should be slightly lower to facilitate heat dissipation. Therefore, the incubation period should follow the principle of high, medium and low.

1.3 The effect of temperature on hatching effect

1.3.1 affecting shelling time and hatching rate

When the incubation temperature is high, the embryo develops rapidly, the chicks increase the shell; the temperature is low, the embryo growth and development is slow, and the shelling time is delayed. According to the test, the hatching rate was the highest in hatching for 21 days at 37.8 °C; the hatching rate was only 20 days at 38.5 °C; the time was only 19 days at 39.5 °C, and the chicks were light in weight and the hatching rate was low; 35.5 °C was delayed until 24 days. And most embryos die in the shell.

1.3.2 affecting the quality of chicks

During the incubation process, if the temperature is too high, too low or high or low, the weak chicks will increase and the rate of health will decrease. If the incubation temperature is high, the chicks will be small, the fluffs will be too short or small, the eyes and sputum will be abnormal, the yolk sac and the intestines will not enter the body in time, etc.; the temperature is too low, the chicks are not lively, the fluff is rough and dry, The abdomen is swollen and soft, the umbilical ring is closed poorly, the ankle joint is red and swollen, and the standing is unstable. When the temperature is high and low, the umbilical ring is often closed, the eyes are closed, the eye is viscous, dehydrated, bent toe or splayed.

1.4 Temperature control

The temperature should be properly supplied according to the temperature characteristics of the embryo, the hatching method and the hatching method. If the incubation is carried out in batches, the temperature of the incubator is controlled at 37.8 °C, and the temperature of the hatcher is 37.0 °C~37.5 °C. The whole batch is incubated with a variable temperature incubation method, and the incubation temperature is 38 °C for 1-7 days. It is 37.8 °C for 8-12 days, 37.6 °C for 13-18 days, 37.0 °C for 19-21 days, and the room temperature of the incubation room is preferably controlled at 22 °C~26 °C. In this way, a better incubation effect can be achieved.

2. Humidity

2.1 The role of humidity

Humidity has a heat-conducting effect, and the embryo can be heated evenly in the early stage of incubation. The late stage of hatching is conducive to the emission of physiological heat of the embryo; improper humidity can affect the evaporation of water in the egg and the metabolism of the embryo; the humidity is also conducive to the shelling of the chick. Under sufficient humidity and CO2 in the air, the CaCO3 of the eggshell becomes Ca(HCO3)2, and the eggshell becomes brittle, which is convenient for the chicks to come out.

2.2 Temperature requirements

The relative humidity of the hatchery and hatchery should be kept at 60%~65%, 50%~60% in the incubator, and 65%~75% in the hatcher.

2.3 Effect of humidity on hatching effect

Embryos have a wide range of adaptation to humidity, which is less sensitive than temperature and generally does not cause a significant drop in hatchability. However, improper humidity control will affect the quality of the chicks. If the humidity is too large, the shelling time will be prolonged. The chicks are soft, the abdomen is large, and the villi are stuck to the egg yolk. The humidity is too small, the shells are released in advance, the chicks are dry and thin, the fluff is dry, and the coke is dry. Sometimes it sticks to the shell.

2.4 humidity adjustment

If the humidity is too large, reduce the number of water trays properly, or strengthen the ventilation to make the water vapor dissipate; if the humidity is low, increase the number of water trays properly, warm the water in cold weather, add cold water in summer, or sprinkle the ground to increase evaporation of water to improve Indoor humidity.

3. Ventilation

3.1 Purpose of ventilation

Supply O2 required for embryo growth and development, discharge CO2; make the temperature inside the incubator uniform; promote heat dissipation of the embryo and prevent self-temperature and over-temperature.

3.2 Ventilation requirements

Keep fresh air, O2 content is not less than 20%, CO2 concentration is not more than 0.5%, but can not affect the temperature and humidity due to ventilation.

3.3 Influence of ventilation on hatching effect

When the concentration of CO2 in the incubator reaches 1%, the embryo is slow to develop, the mortality rate increases, and the fetal position is not correct and deformed. According to the data, the CO2 content in the machine exceeds 1%. For every 1% increase, the hatching rate drops by 15%. When the CO2 concentration reaches 10%, the embryos will all die. Excessive ventilation can affect temperature and humidity, chicks have closed eyes, eye villi sticking, dehydration, and feces are green.

3.4 Ventilation adjustment

In the actual operation, it should be based on the developmental characteristics of the embryo during the incubation process. Generally, the ventilation volume can be smaller in the early stage of hatching. In the middle and late incubation period, as the embryo age increases, the metabolism will be strengthened and the ventilation volume should be gradually increased. Especially in the case of the shell-breaking, the ventilation should be avoided to avoid hatching. The late embryos are suffocated in the shell. Each incubator has ventilation holes. The ventilation is adjusted by opening the ventilation holes. Generally, it opens 1/4~1/3 in the first week, 1/3~1/2 in the second week, and 3/4~ in the third week. 4/4.

4. Turn the egg

4.1 The purpose of turning eggs is to prevent adhesion between the embryo and the shell membrane, so that all parts of the embryo are evenly heated; supply fresh air; help the embryo to move and keep the fetal position normal.

4.2 The requirement to turn the eggs is to turn the eggs once every 1-2 hours and to stop the eggs after 18 days of hatching.

4.3 The effect of turning eggs on the hatching effect If the eggs are not turned over or turned over abnormally for a long time, the hatching rate will be lowered, the embryos will stick to the shell membrane, and the adhered parts will be deformed, such as missing or deformed limbs. According to reports, the whole incubation period did not turn over the eggs, the hatching rate was 29%; the first 7 days after the eggs were turned over, the hatching rate was 79%; the first 14 days after the eggs were turned over, the hatching rate was 95%.

4.4 Turning the egg method The angle of turning the egg should be 90 degrees. It is better to tilt the front and back or 45 degrees to the left and right, and to prevent vibration.

5. Cool egg

5.1 The purpose of the cool egg is to dissipate the residual heat in the incubator, allowing the embryo to get more fresh air, while giving the embryo cold stimulation and promoting embryo development.

5.2 Requirements for cool eggs In colder weather, the incubator is stable in temperature, well ventilated, and the machine is not overheated. Incubate in the hot season, the amount of eggs in the whole box is large, and the eggs should be carried out when the ventilation is poor. Especially in the late incubation period, the metabolism of the embryos should be strengthened. When the temperature is over temperature, the eggs should be strengthened. Every day, every afternoon and afternoon, every time 15 to 20 minutes.

5.3 Effect of cool egg on hatching effect Under normal circumstances, cold egg has little effect on hatching rate. However, in the hot season, when the whole box is hatched, the temperature inside the incubator is not overheated, which will cause the dead embryos and weak chicks to increase, and the hatching rate will decrease.

5.4 Method of cooling the egg Open the air hole or door and window of the incubator, turn off the power, and let the temperature of the embryo egg drop. When using cold eyes, use eyelids to measure temperature, stick the eyelids on the egg, feel cool (32 °C ~ 35 °C), then slowly warm, gradually reach the temperature required for hatching.