The productivity of a layer hen is influenced by multiple factors including gastrointestinal health. Poor gut health can result in a range of health and management problems including dysbiosis, poor uniformity, and susceptibility to avian pathogens such as Campylobacter hepaticus and Pasteurella multocida. Development of the early gut microbiota is increasingly being recognised as an important factor for long-term overall health. Maternal transfer is an important source of bacteria for the neonatal intestinal microflora. Commercial poultry chicks, however, are hatched in a clean environment and have limited contact with parental microbiota. Bacterial seeding of the developing chick gut likely comes from feed and the environment, which may impact the development of a healthy gut microbiota profile. This study evaluated the administration of a live Lactobacillus saerimneri strain at hatch for its impact on the development and stabilization of the gut microbiota during rearing to peak egg production (45 weeks of age). Lactobacillus saerimneri was consistently isolated from 30-60% of birds using culture methods from two days post-hatch to 22 weeks of age. Between 24 and 45 weeks of age, isolation of Lactobacillus saerimneri became highly variable. Analysis of the gut microbiota profiles revealed that the alpha-diversity of the microbiota differed between control and Lactobacillus saerimneri treatment groups. These results indicate that the administration of a live Lactobacillus species to “seed” the developing gut microbiota has the potential to improve productivity and overall health for commercial layer hens.