I feed scratch and peck 24/7 for 10 days, then switch to free access during the day, no feed at night, basically a 12 hour on, 12 hour off cycle. I'm using 17% protein modesto organic. after 10 days or so, start moving the feed to one end and the water to the other end of the brooder, eventually getting about them 5-10 ft apart. I also recommend raising the food and water off the ground as they grow so they have to stand up to eat and drink. they need to be encouraged to stay active or they can go down hill. my 37 cobb 500 CX are 5 weeks old tomorrow, no deaths, still spunky and running around. I will be harvesting at 8 to 9 weeks.