but my birds are not in a 1 sqft cage with food passing by them 24/7.
Industrial broiler chickens are not raised in cages and the only day that they have 24 hours of light (when they can eat) is the first day on the farm. Next are days with decreased light then they have an increasing light schedule as they age. Commercial producers would consider 12on/12off light programs totally in appropriate for the well being of the bird.
I go on the science based upon body builders.(You don't feed a body builder less protein to bulk him up).
Human body building science and muscle mass production in chickens is not the same thing. Their bodies will easily attain the maximum muscle mass obtainable on an adequate diet. No matter what you feed them and how much you work them out there is no way to obtain more muscle (meat). You can for sure increase the strength of that muscle and increase the muscle tone but "bulk them up", no. Unless you consider just getting them bigger overall to be "bulked-up." That is just pushing hard for gain. The industry does not overtax the systems in that manner. It is un profitable because it causes health problems and has a lower return on feed cost.
More exercise means more protein needed to bulk-up.
To support exercise more carbohydrates and fats are needed. Human or avian. Yes to build more muscle protein is needed - if the organism can produce it. Which a chicken cannot.
I have some very active 7 week-old 7-8 lb meaties running around my yard chasing bugs, eating grass, and enjoying freedom. That is something not included in that 50 years of research. If I chose to keep my birds in a cage or pen where they couldn't move and only had the option to eat, then I would probably follow that chart. On the contrary, my birds are vastly different. They are not the lazy bums everyone on here mentions, partly because I have never treated them like that, they burn calories. If there was a hint of stink with them, I would be the first person on here watching people raise them from afar because my wife would not allow the stench around the house. Like I said, this is what works for me and I am not saying the other ways are wrong.
Hey that is great! Please just don't parrot and promote the misconceptions and ignorance of the facts about the industry.
It amazes me that backyard poultry people will not use what they can learn from the industry. Some of it applies and some does not but as Mr. Spock said- "it is unwise not to consider all the possibilities".