1. The purpose of broiler breeding industry is to focus on ventilation: 1. Reduce harmful gases in the house, discharge harmful gases such as NH3 and CO2, and increase oxygen; ensure the health of chickens. 2. Adjust the humidity in the house, reduce the humidity in the house, and keep the litter dry; 3. Reduce the temperature in the house and increase the feed intake. 4. Increase the utilization rate of the chicken house and improve the stocking density. High-density rearing has a large air change and requires good ventilation. 5. It can prolong the service life of the equipment. 6. Ensure the normal growth of chickens, improve feed conversion rate, and obtain reasonable economic benefits. The cardiopulmonary function of fast and large broilers cannot adapt to the needs of rapidly growing muscles for blood oxygen, so a good ventilation environment is more necessary. 7. Excessive ventilation reduces the temperature, humidity and dust in the house, which can easily induce respiratory diseases. 8. Insufficient ventilation results in delayed growth, weak legs, ophthalmia, ascites caused by hypoxia, heat stroke in the season, and respiratory diseases in winter. 2. The rules and effective control of ventilation: According to scientific experience, the ventilation of broiler breeding * follows the following rules: At the age of 1-2 weeks, heat preservation should be given priority to, and proper attention to ventilation; After age, ventilation should be given priority to unless in winter. --fiber fabric duct