Key points of winter ventilation management for modern caged chicken houses(2)

Adjust the temperature difference of the chicken house

In winter and spring, we must not only consider the temperature and effective ventilation of the chicken house, but also consider how to better adjust the temperature difference in the chicken house to reduce the harm of cold and heat stress to the chickens. The temperature difference is not only the temperature displayed by the environmental controller. The temperature difference displayed by the probe and the thermometer will cause the measured temperature of the chicken house to be different due to the different position and height of the temperature probe hanging.

The weather is cold in winter and spring, the temperature difference between day and night increases, and the temperature difference between inside and outside the house increases. At the same time, in order to ensure the temperature and ventilation of the chicken house are passively reduced, the various temperature differences in the chicken house increase and it is difficult to control. Sometimes we cannot change the natural environment outside the house. The natural temperature difference formed by the season, climate, and weather can only be reduced by adjusting the heating, air inlet, and number of fans in the chicken house, coordinating the balance of wind pressure, wind speed, and air volume in the air path, and cooperating with scientific feeding management to reduce the external environment. The impact on the interior of the chicken house thereby reducing the impact of temperature differences on the health of the chickens.

4. Reasonably adjust the air inlet

First, ensuring the correct air intake method to prevent the chickens from getting cold is the key to ventilation in winter and spring.

In the cold season, due to the large temperature difference between the inside and outside of the chicken house, the fresh air entering the chicken house must maintain a certain wind speed and direction so that the fresh air entering the chicken house and the warm air in the chicken house can be fully mixed and fully preheated before contacting the chickens. The flocks should be protected from cold air blowing directly onto the chickens, causing cold stress in the flocks.

Second, correctly choose a safe air inlet method

In the cold season, different air inlets are used for ventilation of the chicken house, which will have a great impact on the comfort of the chickens, as well as the growth performance and health of the chickens. Choosing different air inlets results in different air inlet methods. In fact, the ventilation mode changes, such as using ventilation ducts, small windows, water curtains, air inlets of the same area, and the same number of fans. , the wind speed, wind direction, and air flow in the chicken house are different, and the local unit air exchange volume is completely different, and the cooling effect on the chicken house is different.

Third, different air inlets form different airflows

Choosing an adjustable damper air inlet in winter and spring has the best effect, because it can make the cold air entering the chicken house flow upward to the top of the chicken house. When the position of the air inlet damper is properly adjusted and a certain static pressure is maintained in the chicken house, the air inlet can be used more efficiently. The airflow entering the chicken house at high wind speed will flow along the top of the chicken house to the center of the chicken house, where it will mix with the warm air in the chicken house, so that the chickens will be less likely to suffer from cold stress.

If the air inlet without an adjustable damper is used, the cold air entering the chicken house will flow in a horizontal direction and then fall. In this way, the cold air entering the chicken house will not have enough time to mix with the warm air above the chicken house to preheat, forming a cold air. The air settles in advance and directly contacts the upper chickens, causing cold stress in the chickens. Using water curtains in winter has the greatest risk of air inlet. Cold air will sink directly, causing local cold stress, and should be avoided.

5. Reasonably set the negative pressure value of the chicken house

First, negative pressure requirements are very strict in the north, which is related to the success or failure of breeding. Once the ventilation negative pressure setting is unreasonable and causes continuous cold stress in the chickens, disease infection and spread will easily occur.

Negative pressure is not the need of chickens or people, but the ventilation needs of the chicken house and the season. Negative pressure ventilation must be used in winter and spring to complete the effective ventilation of the chicken house, and use negative pressure to allow fresh air from the outside to reach the house. Designate the required position within the chicken house to ensure uniform wind speed and air volume inside the chicken house to achieve the best ventilation effect. Negative pressure that is too large or too small can easily form ventilation dead corners, causing local cold stress to increase. Negative pressure is a dynamic indicator among variables and needs to be relatively stable. Excessive negative pressure will affect the oxygen content and affect the growth, development and health of the chickens. At the same time, it affects the efficiency of the fan, resulting in a waste of electricity; if the negative pressure is too low, the air in the chicken house cannot effectively circulate, and dust pathogens in the house cannot be effectively discharged out of the house. At the same time, local cold and heat stress is increased, forming a ventilation dead zone. Increase the temperature difference within the house.

Second, different seasons, different chicken house structures, and different feeding modes require different negative pressure values.

Generally, the negative pressure value in the cold seasons of autumn and winter is relatively higher than that in summer, because the hot weather in summer can ensure that the air level reaches the middle of the chicken house, while in winter, it is necessary to ensure that the cold air can rush to the top of the chicken house and mix with the hot air in the house. Achieve the purpose of not falling into the cold wind. The specific negative pressure value setting should consider the height, span, curvature of the roof, the position and height of the side wind windows, the direction of the deflector, the refraction of the beams, etc.

Generally, the negative pressure value required at night is higher than during the day, especially when the temperature difference between day and night is large. Because the temperature difference between the inside and outside of the house is relatively small during the day, the cold air entering from the outside requires a relatively short preheating time. The temperature drops at night and the temperature difference between inside and outside increases. , if the same ventilation time during the day is used to preheat the same amount of low-temperature cold air, the same preheating effect cannot be achieved, so the unit air intake volume should be appropriately reduced while the fan time remains unchanged.

Third, in the cold seasons of winter and spring, strong windy weather has a great impact on breeding. Improper ventilation will cause disease incentives.

Especially modern environmentally controlled chicken houses that use negative pressure control windows and fan ventilation. Because the negative pressure value is affected by the external wind direction and wind force. Negative pressure ventilation relies on the negative pressure value to control the opening angle of the small windows. The opening sizes of the small windows on both sides are the same. This can easily cause too much cold air to enter the small windows downwind and cause cold stress. At the same time, strong winds will change the load inside the house. If the pressure value and the fan remain unchanged, the small window will be too large or too small when opened, which directly affects the ventilation mode of the chicken house. Usually the wind direction affects and determines the adjustment of the side windows. It is generally required to selectively reduce or even close the side windows on the downwind side (especially for small day-old chickens) to prevent cold wind from pouring into the chicken house. At the same time, reduce the number of fans and Appropriately reduce the leeward side windows.

The strength of the wind directly affects the ventilation volume of the chicken house. If our chicken house is poorly sealed, mechanical ventilation is rarely used or dared to be carried out under the influence of strong winds. As the wind force changes, it is necessary to promptly adjust the fan usage, ventilation mode, and side window arrangement and size.

Otherwise, improper handling will cause very serious cold stress to the chickens, thereby reducing the resistance of the chickens and making the chickens susceptible to disease. Chicken houses that usually use ventilation ducts and small window guide cloth are relatively less affected by windy weather.

6. Develop a scientific and reasonable ventilation mode

Regarding the ventilation mode, whether it is intermittent ventilation or continuous ventilation; high negative pressure and high wind speed ventilation; or low negative pressure and low wind speed ventilation; there is no right or wrong or good or bad in itself. Because the ventilation mode needs to be flexibly used and converted according to different breeding modes, different seasons, different regions, and different ages, combined with the overall structure of the chicken house, environmental control equipment, heating equipment, temperature differences, etc., only practical operators can use it wrong! For example, it is not advisable to completely apply the successful ventilation models of ground and net culture to cages, or to apply the successful models of summer and autumn to winter and spring.

No matter which method is chosen for ventilation, you must stand on the top of the cage at each time period to personally feel the wind speed and direction of the air entering the small windows at each point. Especially at night, you must feel whether there is any loose wind blowing the chickens, and observe Whether the incoming air can reach the middle of the roof, whether there are ventilation dead corners, etc., so that the size and angle of the air inlet through the small window can be adjusted more promptly and better, and the fan unit can be adjusted.

When choosing a ventilation method, we must not only consider the effective ventilation of the chicken house, but also consider how to better adjust the temperature difference in the chicken house and reduce the harm of cold and heat stress to the chickens. Special attention should be paid to the physical comfort of the chickens, because if you want to raise chickens well, you must provide the chickens with a comfortable small environment suitable for growth. The most important thing in ventilation management is to grasp the interdependent and mutually restrictive balance between temperature, humidity and ventilation, so as to keep the indoor environment relatively constant.

Therefore, the best ventilation mode is to choose the most reasonable, effective and lowest-risk ventilation mode that is most suitable for your area and chicken house.

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