The present invention generally relates to a strain of Lactobacillus probiotic bacteria and a poultry vaccine for use in the in ovo vaccination of poultry, wherein said strain and said vaccine are administered to an embryonated poultry egg. Compositions suitable for use in an in ovo vaccination protocol for poultry comprising a strain of Lactobacillus probiotic bacteria and a vaccine diluent which is suitable for the poultry vaccine to be used in said vaccination protocol are also provided, as are suitable kits for use in the invention.
