You can get rice bran at any local feed store, a lot of people feed it to livestock also. Rice bran is a by product of milling rice, the part that comes off durning the kernal polishing I believe. They used to throw this away like a lot of other things until there was a market, now it's getting higher.
Just ask around at the feedstores for it. As far as feeding it I just pour it in a big pile, however if it get's wet it will mold and nothing will touch it so you have to be wise how much you put out depending on rain. Some people put it in throphs to keep it from getting wet.
Rice bran is a by-product of the milling of rice. It consists mostly of the bran layer and germ of the rice with some fragments of hull and broken rice.
The calcium level in rice bran will vary with the amount of added calcium carbonate. When the amount of added calcium carbonate exceeds 3 percent (total calcium exceeds 1.2 percent), then the percentage of calcium carbonate must be stated in the product name.
Rice bran is similar to oats in crude protein, fat, fiber and energy. It is a palatable feedstuff, which can be included in the grain mixture at a rate of up to 25 percent or fed at a rate of up to 8 pounds (3.6 kg) per cow per day.