...but there is something about either the corn or the decreased protein that packs on muscle and fat in a way that higher protein feeds don't seem to do. The way I understand it, when fed higher protein, the birds grow more skeletally and once you decrease the protein levels with added corn, their skeletal growth slows and their muscles start bulking. So, at risk of being repetitive, the idea is you change over once your birds have the "right" frame (which of course is subjective based on what you're looking for) and you transfer as much power as you can in the last 2-4weeks to building the meat that will ultimately be eaten. I've noticed a significant increase in the weight of my broilers after starting experimenting with this method of feeding.