This trial was carried out to find out the effects of the parent flocks and the hatching time of broiler chickens on the production traits and bacteriota development of animals. Two times 730 hatching eggs were collected from two different parent flocks with age of 22-23 and 65-66 weeks. In the hatchery both groups were divided into two subgroups, when the day-old chickens were separated according to their hatching time. A feeding trial was carried out afterwards, using the 4 treatments in 6 replicate floor pens, feeding commercial starter, grower, and finisher diets, that contained all the nutrients according to the breeder’s recommendations. The day-old chickens of the parent older flock and those hatched later were heavier and this advantage of the birds remained until end of the production period. The different age and origin of parent flocks failed to modify the microbiological parameters of the chicken’s ceca. However, the hatching time significantly influenced the different bacteriota diversity indices. The late hatched chickens showed higher Bacteroidetes and Actinobacteria and lower Firmicutes abundances at day 11. These treatments resulted differences in the main families, Ruminococcaceae, Lactobacillaceae, Bacteroidaceae. These differences could not be found at day 39.