Effects of Egg Size and Different Levels of Humidity during Incubation Period on the Embryonic Development, Hatching Percentage and Chicks Yield of Broiler Breeder

Background: This experiment was performed to investigate the effect of humidity and egg size on the hatchability, embryonic development and chicks yield in ROSS 308 broiler breeder flock. Methodology: The study was conducted in a completely randomized design with a 3×3 factorial arrangement. The treatments involved three levels of wet bulb humidity (°F WB) including 82, 82.5 and 83°F and three different egg sizes including small, medium or large. Results: The main effect of humidity level on the total and fertile hatchability (%) as well as the weight of one-day-old chicks were significant (P