Percent ain't Mass

I’ve been making up all of the food for my chickens and they’re healthy and content but I would really like to understand the daily minimum nutrition required for one chicken.

I am going a bit dizzy from the sources I’ve been able to find because they talk about, for example percent protein, but never seem to state the volume to feed one bird. As if feeding a hen a bushel or a teaspoon daily are the same as long as they contain 16% protein.

Does anyone know or have a reference they could recommend that gives the daily nutritional requirements for a single chicken in grams (not percent)? I’m sure breed, activity, age and size probably matter, just like us humans.

I’ve got bared rocks and heritage RIRs. Also I’m in suburban New England so they don’t get to forage daily. Unless someone can supervise an outing they eat what I give them and whatever dares to flit into the run. So I worry sometimes about everything being ok.

http://extension.psu.edu/animals/poultry/topics/general-educational-material/the-chicken/modern-meat-chicken-industry wrote:On average a broiler consumes about 9 pounds of feed (current cost of about $1.50 or $.30/pound) and reaches 5 pounds (live weight) in 5 weeks..

Justin Rhodes, 'the permaculture chicken guy' has several vlogs on raising chicken on youtube.  Some of his solutions for low or no-cost feed won't be useful to a suburban property owner.
Other suggestions, such a getting breeds that eat less than others, or limiting the number of chickens to what is needed to reach your objectives, may be more applicable for your situation.

One thing Justin Rhodes has noted is that feeding your chickens more than 1/3 or a pound a day just puts on the fat.
Interesting to note that the average consumption of a broiler according the psu.edu is also just less than a 1/3 of a pound a day--5 weeks--35 days--divided into 9 lbs

https://abundantpermaculture.com/i-cut-my-chicken-feed-bill-100

https://abundantpermaculture.com/how-to-feed-chickens-without-grain/

Want to grow your own protein and produce up to 1.5 pounds per week on a footprint of 1.5 square feet?

http://velacreations.com/howto/mealworm-farm/