EVALUASI KETINGGIAN TIER BERBEDA TERHADAP PERFORMA AYAM STARTER PADA SISTEM KANDANG CLOSED HOUSE

The starter phase constitutes a critical period in the growth of pullet chickens,
playing a significant role in determining performance and uniformity in subsequent production stages. In a closed house housing system, differences in tier height may lead to variations in microclimatic conditions, which can subsequently influence bird performance. This study aimed to evaluate microclimatic differences and to assess the effect of tier height on body weight gain and uniformity during the starter phase. The research material consisted of 108 Isa Brown strain pullets aged six weeks, reared in a closed house system for 35 days. The primary variables observed were body weight gain and uniformity, while supporting variables included temperature, relative humidity, air velocity, and the Heat Stress Index (HSI), which were analyzed using a quantitative descriptive method. The results indicated that birds housed on the upper tier exhibited a higher growth rate (6.39%) compared to those on the lower tier. The average uniformity value on the upper tier was also higher (0.92%) than that observed on the lower tier. These findings were associated with more favorable microclimatic conditions on the upper tier, characterized by lower humidity and reduced heat stress levels. It can be concluded that differences in tier height influence microclimatic conditions (particularly temperature and humidity), which in turn affect growth dynamics and uniformity of starter-phase pullets.