I get straight run and divide my males from the females at 5 weeks because I finish off with 20% chick starter for their last 2 weeks of life. Although the males do exhibit a little more aggression (sometimes they rush me when I'm giving them their feed), mostly they are fat and lazy and too young to have enough hormones to fight with each other. Males turn out quicker, between 6 and 7 weeks. They tend to be a little bigger too. I factor my costs on my flock as a whole, both male and female, so I can't say for sure, but I think your costs would be just a bit lower with the males since you don't keep them around as long.