rhode island reds are *typically* great layers and active birds. protein content should be on the higher end for them, also watch for calcium deficiencies - usually shows up as soft shells first.
i have my feed custom made, and change the formula as needed. my chickens are in breeder's pens with some occasional outside access, so my feed has to be more nutritionally complete than the average person's.
this is the recipe:
375 lbs cracked corn
50 lbs of oats
75 lbs of wheat
200 lbs range bird pellets (hog pellets will work too) 24% protein
50 lbs black oil sunflower
25 lbs of wet molasses
50 lbs alfalfa pellets - or feed one alfalfa cube per 3 chickens per day.
we also feed a few meal worms a couple times a week for added protein and treats.
corn is a filler, and helps keep them warm in the winter
oats are an additional filler with a higher protein content than corn, but typically wont add any extra fat on the chickens.
wheat contains several oils and nutrients chickens need, not to mention almost the perfect protein ratio. some old time farmers used ground wheat to start chicks.
the range bird pellets are a nutritionally complete feed, im not sure how available they are in other states. they were created here in ohio.
black oil sunflower adds oil and some protein to the feed, if your chickens look dull add more sunflower seeds
molasses has several effects on chickens, increased thirst (that's a good thing), and several micro-nutrients. it may also make them more broody, and if you hatch the eggs the ratio of pullets to cockerels will probably increase.
alfalfa pellets are because my chickens don't always have access to grass.
there is some soy in the range bird pellets, but i don't add any extra. soy blocks some protein absorption. you may want to research soy and anti-nutrients.
it is best to get self pollinating varieties as often as you can- make sure your soil is complete so the grains can absorb the nutrients and pass them on.
you may also want to research fermenting your grains. I'm fairly new to it, its cheap to do and appears to have several benefits to the chickens. probiotics are created by the process and several of the nutrients become more available. my own experience is slightly less feed, shinier birds with less sniffles. overall laying has been a little better, egg shells are of better quality.
now for the down side - no matter what grains or additives you decide to use, all are going to have positive and negative effects on your chickens. you have to adjust for optimum performance, and just use your own judgment.