On d 56 of each trial, 20 birds (10 males and 10females) from each room were randomly selected forprocessing, and weighed after being subjected to a 12-h overnight feed withdrawal period. This live weight(post-feed withdrawal) was used to calculate wholecarcass yield. Thereafter, the birds were placed incoops and transported to the Mississippi State Uni-versity poultry processing plant. Birds were electri-cally stunned, bled, scalded, mechanically picked, andmechanically eviscerated. Whole hot carcass (withoutneck, giblets, abdominal fat pad) and abdominal fatpad including leaf fat surrounding the cloaca and giz-zard were weighed. Carcasses were then split into frontand back halves and placed on ice for 4 h. After chill-ing, the front halves were deboned to obtain weights ofskinless, boneless breast fillet (pectorals major muscle)and breast tender (pectorals minor muscle). Abdominalfat pad and total breast meat yield (sum of pectoralsmajor and minor muscles) were determined from thesum of the fillet weight and tender weight