The objective of this analysis was to evaluate the effects of raising broilers under sex separate and straight-run conditions for 2 broiler genetic lines. One-day-old Ross 308 and Ross 708 chicks (n = 1,344) were sex separated and placed in 48 pens according to rearing type: sex separate (28 males or 28 females) or straight-run (14 males + 14 females). There were 3 dietary phases: starter (zero to 17 d), grower (17 to 32 d), and finisher (32 to 48 d). Bird individual BW and group feed intakes were measured at 12, 17, 25, 32, 42, and 48 d to evaluate performance. At 33, 43, and 49 d 4 birds per pen (straight-run pens 2 males + 2 females) were sampled for carcass yield evaluation. Data were analyzed using linear and non-linear regression in order to estimate feed intake and cut-up weights at 3 separate market weights (1,700, 2,700, and 3,700 g). Returns over feed cost were estimated for a 1.8 million broiler complex for each rearing system and under 9 feed/meat price scenarios. Overall, rearing birds that were sex separated resulted in extra income that ranged from $48,824 to $330,300 per week, depending on the market targeted and feed and meat price scenarios. Sex separation was shown to be especially important in disadvantageous scenarios in which feed prices were high. Gains from sex separation were markedly higher for the Ross 708 than for the Ross 308 broilers. Bird variability also was evaluated at the 3 separate market ages under narrow ranges of BW that were targeted. Straight-run birds decreased the number of birds present in the desired range. Depending on market weight, straight-run rearing resulted in 9.1 to 16.6% fewer birds than sex separate rearing to meet marketing goals. It was concluded that sex separation can result in increased company profitability and have possible beneficial effects at the processing plant due to increased bird uniformity.