INTRODUCTION: HEAT STRESS (HS) IS INVOLVED IN THE POULTRY PRODUCTION INDUSTRY, PARTICULARLY IN WARMTH REGIONS OF THE WORLD SINCE OF THE RESULTING WEAK GROWTH PERFORMANCE, IMMUNOSUPPRESSION AND HIGH MORTALITY RATE. CHLORELLA IS UNICELLULAR GREEN ALGAE THAT CONTAIN ESSENTIAL AMINO ACIDS, PROTEIN, MINERALS, VITAMINS, DIETARY FIBER, AND A GREAT RANGE OF ANTIOXIDANTS, BIOACTIVE SUBSTANCES AND CHLOROPHYLLS. ...