The additive Miya-Gold® consists of viable cells of Clostridium butyricum FERM BP-2789.The additive is currently authorised in the EU for use as a feed additive for chickens for fattening, chickens reared for laying, turkeys for fattening, turkeys reared for breeding, minor avian species (excluding laying birds), piglets (suckling and weaned) and piglets of minor porcine species. The authorisation for chickens and minor poultry species for fattening and reared for laying is at a minimum level of 2.5 × 108 CFU/kg complete feed. The applicant has requested to lower this level to 1.25 × 108 CFU/kg feed. The Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) did not consider any of the five long-term trials and one pooled analysis of two of them as supporting evidence for the efficacy of the additive at the lower dose due to the incompliance of the husbandry conditions in which the chickens were reared with those indicated in Directive 2007/43/EC. Owing to the lack of adequate data, the Panel is not in the position to conclude on the efficacy of Miya-Gold® at 1.25 × 108 CFU/kg feed for the target species.