The Effect of Light Intensity and Temperature-Humidity Index on Egg Performance and Growth Rate in Laying Hens Raised in Different Cage Tiers

The aim of this research is to evaluate the effects of light intensity and the temperature-humidity index (THI) on egg performance and growth rate in laying hens reared on different cage tiers. Additionally, the study seeks to un-derstand the sensitivity and efficiency of chickens' comfort conditions under various climatic environmental conditions. Brown layer Hyline Brown hens were used as the animal material. In the experiment, 392 hens were housed in a total of 56 cages, with 7 hens per cage in a 4-tier cage system. During the experiment, live weights, growth rates, egg pro-duction, and egg weights of the hens were recorded and correlated with the THI and light intensity values measured in front of each cage. The results indicated that hens on the upper tiers had higher live weights, body weight gains, growth rates, egg production, and egg weights compared to those on the lower tiers. A negative relationship was found between the THI value and both growth rate and egg production. Increasing THI values negatively affected both body weight and egg production. Significant positive relationships were observed between light intensity and egg weight, egg production, and average egg production. In conclusion, environmental management and physiological factors are crucial in optimizing the performance of laying hens. Appropriate housing conditions, including optimal light intensity, and temperature management, are essential for maximizing both growth and reproductive performance. Additionally, achieving an ideal body weight at the beginning of the productive period is a crucial for egg production.