PROBLEM TO BE SOLVED: To provide a feeding stuff which can increase a gain in a former period of fattening of a meat-type chicken, and a method of increasing the gain in the former period of fattening.SOLUTION: The feeding stuff for a meat-type chicken is a pellet formed by pressing a feedstuff material including ground product of chaff and/or rough rice. The feeding stuff for a feeding period includes ground product of chaff and/or rough rice. The feeding stuff may be used for increasing a gain in the former period of fattening. A method of increasing a gain for the meat-type chicken, a method of improving a breeding environment of the meat-type chicken, and a method of improving bacterial flora in the intestinal tract of the meat-type chicken are characterized in supplying the feeding stuff for the meat-type chicken or the feeding stuff for the feeding period in the former period of fattening.
