As a significant factor can be the first week mortality for broiler flocks to indicate of the health status and performance of the broiler flocks during the rearing period. Several factors, which includes animal related factors, egg and incubation related factors, and external factors, shown to affect the first-week mortality. Animal related factors are discussed that strain, sex, and breeder flock age besides The first-week mortality could be affected by egg source (clean, nest, floor or washed eggs), egg weight, egg storage duration, egg shell conditions (dirty, stained, clean), and incubation environmental properties. The first-week mortality can provide information not only about farm environmental conditions, but also about sources of the eggs or the chicks besides infections. Therefore, there is a need to put more effort into the first 7 days of the chicks’ life to make sure they develop good drinking and feeding behavior and thus quickly can cope with potential challenges.