The additive Alterion NE ® is a preparation containing viable spores of a strain of Bacillus subtilis. The additive is intended for use in feed for chickens for fattening and chickens reared for laying at the proposed dose of 1 × 108 CFU/kg complete feedingstuffs. B. subtilis is considered by EFSA to be suitable for the qualified presumption of safety approach to establish safety. As the identity of the active agent was established and the lack of toxigenic potential and of resistance to antibiotics of human or veterinary clinical significance demonstrated, the additive is presumed safe for the target species, consumers and the environment. Alterion NE ® is not a dermal irritant but is irritant to eyes and should be considered a potential respiratory sensitiser. In the absence of data, no conclusion can be drawn on the dermal sensitisation of the additive. Alterion NE ® at the recommended dose 1 × 108 CFU/kg feed has the potential to improve the zootechnical performance of chickens for fattening. This conclusion can be extended to chickens reared for laying when used at the same dose. B. subtilis DSM 29784 is compatible with monensin sodium, narasin/nicarbazin, salinomycin sodium, lasalocid sodium, diclazuril, narasin, maduramicin ammonium, robenidine hydrochloride and decoquinate at the highest authorised levels.