Scienceline Publications Online Journal of Animal and Feed Research 2228-7701 6 6 2016 September IMPACT OF GENDER DETERMINATION THROUGH VENT SEXING ON COBB-500 BROILER PERFORMANCE AND CARCASS YIELD 125 129 http://www.ojafr.ir/main/attachments/article/124/OJAFR%206(6)%20125-129,%202016.pdf EN Adnan YOUSAF Sadiq Poultry (Pvt) Limited, Rawalpindi, Pakistan The study was conducted in order to explore the effect of separated sex rearing of broiler production performance. Total no of (n=24,000) Cobb-500 birds were reared for 42 days and divided in two group’s A =12000 male and B= 12,000 females, according to their sex with 4 replication in each treatment where each replication had 3000 birds. They were provided the same feed and water ad libitum for the whole study. Initial body weight, temperature, humidity, feed intake, weekly body weight, mortality and final live weight of broiler were recorded. The study clearly shows significant differences (P 0.05) in term of body weight gain and FCR for males chicks compare to females. Male birds also showed significantly (P 0.05) better dressing percentage than female group. Male chicks had significantly (P 0.05) larger chest circumference females birds. The cross with the fastest growth rate also had the highest mortality. Mortality percentage was high in male chicks 4% then female’s chicks 2%. The most profitable choice will be dependent on whether whole birds or parts are marketed and the relative values of the parts. All these findings together revealed that in separate sex growing male chicken showed better performance in terms of more production. Cobb-500 broiler Vent Sexing Growth Performance FCR Carcass