Compositions for oral administration to a young poultry bird, such as a chicken, that comprise cecal material from adult poultry birds and saline are disclosed. The compositions can be used to increase body weight gain in a poultry bird by administering them to a young bird by oral gavage. The compositions may also be used to increase feeding efficiency in a poultry bird. Further disclosed are compositions for application to poultry litter, for example, chicken litter, that are prepared using the cecal material from adult poultry bird. The compositions may be used to prevent or reduce colonization of the chicken gut by pathogenic bacteria. Also disclosed are method of selecting for bacterial strains with probiotic potential.
