In ovo feeding refers to a method of delivering nutrients or supplements directly to the developing embryo inside the egg before it hatches. This method is commonly used in the poultry industry to improve the health and performance of the chicks after they hatch.  One specific application of in ovo feeding is the use of probiotics. Probiotics are beneficial bacteria that can help improve gut health and overall immune function. By delivering probiotics directly to the developing embryo in ovo feeding can help establish a healthy gut microbiota early on leading to improved health and performance in the hatchlings. Probiotics can compete with harmful bacteria in the gut preventing them from colonizing and causing infections. This can reduce the need for antibiotics as the chicks are better equipped to fight off infections naturally. This can lead to better growth rates and feed conversion efficiency in the chicks.  In ovo feeding probiotics is a relatively new and evolving technique in the poultry industry. Research is ongoing to optimize the delivery methods doses and types of probiotics used. Overall, in ovo feeding probiotics is a promising approach to improve the health and performance of poultry. By supporting the gut microbiota early on in the development of the chicks the benefits can be seen throughout their lifespan. Continued research and advancements in in ovo feeding techniques will likely lead to further improvements in the future.