The breeding companies of layers and broilers do provide specific suggestions for their breeds, as the diversity in type they can supply is quite large.
I would take those advices certainly into consideration as they are tailored to their stock.
The most convenient way of feeding chickens is with a balanced pelleted ration, whether the birds are confined indoors or allowed to range outdoors. Most diets contain corn for energy, soybean meal for protein, and vitamin and mineral supplements. Commercial rations often contain antibiotics and arsenicals to promote health and improve growth, coccidiostats for combating coccidiosis, and sometimes mold inhibitors. However, it is possible to obtain unmedicated feed-check feed labels to see if they contain feed additives.
In the industry, the feed is pelleted so the bird can eat more at one time. Chickens are nibblers and make frequent trips to the feed trough for small meals, which requires energy. Pelleting reduces the amount of energy required for a bird to feed. However, many producers of pasture-based, "natural" poultry believe that the meat is better when the bird receives more exercise.
If the bird is eating a fibrous diet, grit such as oyster shells is supplied to aid in grinding up coarse feed in the gizzard. Industry birds usually don't use grit because the diet is low in fiber. Outdoor birds also pick up small stones.
Different rations are often used, depending on the production stage of the bird. Starter rations are high in protein-an expensive feed ingredient. However, grower and finisher rations can be lower in protein since older birds require less. A starter diet is about 24% protein, grower diet 20% protein, and finisher diet 18% protein (1). Layer diets generally have about 16% protein. Special diets are available for broilers, pullets, layers, and breeders. Whole grains can also be provided as scratch grains.
Access to clean water is important. Levels of total dissolved solids above 3000 ppm in the water can interfere with poultry health and production.
you can use NRC as for research purpose otherwise most of the private companies are feeding as per the strain and breed to get maximum production. In India BIS feeding standard is used
It is better to follow the specifications of the breeders. However, NRC standard can also be used by using 100% and 75 and 125% of the recommended requirements in trials so as to establish the best requirements for your location.
In formulating your diets you should also take into account how well the levels of critical nutrients in your feedstuffs are known to you.
If you can rely on real analytical data or constant quality of the feedstuffs your margin can be less than when you have to rely on table values which might deviate substantially from the batch at hand.
The best standards for pure strains of commercial animals are the ones issue in their catalog. However, some international tables such as NRC or … are preferred by most of breeders. Some breeders also use different sources for requirement table and ingredient tables and I believe this is the best way.
So I suggest the specific requirement table that published along with one new strain and ingredients table of most similar with your feeds quality.
nrc is avaiable for all type of animals...along with this all the nations are following their own standards depending on their livestock potential and the environment conditions... for an instance. india is having its own ICAR standards
I have almost exclusively used the NRC tables for monogastric species, bearing in mind that the values may not necessarily reflect the conditions (feed quality, genetics, management, climate, etc) in a tropical environment: it is always a good idea to make small allowances for the differences - nutrient allowances. The feeding standards provided by Breeding Companies have the same limitations as the NRC
It is obvious that the best way to know feed ingredients characteristics, is their analysis with reliable technology such a NIR (if it is accessible). So I think that use non-commercial tables like (Brazilian table) is more appropriate.