現行台灣傳統式雞舍飼養環境溫度控制評估與改善設計之研究

Abstract

雞舍內的氣流、速度和溫度會影響雞隻的健康，雞舍熱環境條件的優劣決定雞隻的產蛋表現。台灣等熱帶和亞熱帶地區的農業生產所面臨的挑戰為高溫對於蛋雞的負面影響。目前台灣仍以傳統式雞舍的飼養佔九成以上為大宗。因此研究的目的為以傳統式雞舍的重新設計來提供雞隻理想的溫度生活環境，達成保障動物福利、提升蛋類食品安全，以及人類動物共享健康 (One Health)的目標。 研究利用多孔性材質模型將雞籠及雞體簡化為具相同阻力特性的長方體，採用計算流體力學 (Computational Fluid Dynamics，CFD)的方式進行模擬。透過數值模擬，得知流場內各位置的速度和溫度分布。研究分別設計了兩種進風處高度和三種風扇尺寸，以分區通風和側向抽氣的通風策略進行六種改良式傳統雞舍模型降溫效果的比較。 模擬結果發現模型1、4的雞籠平均環境溫度最低，最多可降至35°C，模型3為最高溫，最多降至36°C，兩者相差約1°C。以風扇風速預測雞籠平均環境溫度的直線和二次迴歸方程式已建立，其R2值均大於0.8，代表在一定的範圍下，抽氣速度越高，雞籠平均環境溫度會越低。 預測方程式可供未來雞舍環控系統發展用。為了滿足雞隻正常生產所需的溫度環境，雞舍可採用研究設計的改良式模型，搭配研究所建立具可信度的抽氣速度-雞籠平均環境溫度迴歸方程式，調整風扇風速來下降雞籠環境溫度。

The airflow, velocity and temperature in chicken cages directly affect the health of chickens. The thermal environment of chicken house determines the performance of egg-laying hens. The challenge for agricultural production in tropical and subtropical regions such as Taiwan is the negative impact of high temperatures on chickens. At present, Taiwan is still dominated by traditional chicken houses, accounting for more than 90%. Therefore, the purpose of the research is to provide the ideal temperature living environment for chickens through redesigning traditional chicken house. The redesigned models can achieve the goals of protecting animal welfare, improving egg food safety and ensuring One Health. We use the porous media model to simplify the chickens in the cages into cuboids with the same resistance characteristics, using Computational Fluid Dynamics (CFD) method for simulation. Through numerical simulation, we know the velocity and temperature distribution of each position in the flow field. The ventilation strategy is partition ventilation and side air extraction. The study designed two heights and three fan sizes, comparing the cooling effects of the six models. The simulation results found that the average environmental temperature of the chicken cages of model 1 and 4 was the lowest, and that of model 3 was the highest. Model 1 and 4 can be reduced to 35 °C at most, and model 3 can be reduced to 36° C. The difference between the two is about 1 °C. Linear and quadratic regressions to predict the average environmental temperature of the chicken cage by fan velocity have been established. The R2 values were all greater than 0.8. In a certain range, the higher the velocity, the lower the average temperature. The regressions can be used for the development of chicken house environmental control system. The redesigned models and regressions can be used to adjust the fan velocity to achieve the ideal temperature of chicken cage environment.