Abstract. In the presented publication, the main attention was paid to the effect of the productive age of laying hens of the parent flock of meat crosses “Ross 308” and “Cobb 500” on certain morphological and biochemical parameters of breeding hatching eggs. All investigated parent flock hens were divided into 4 productive ages: the first – 28–30 weeks, the second – 31–40, the third – 41–50 and the fourth – 51–60 weeks of the productive age of the bird, respectively. An average sample of breeding hatching eggs was made in the early morning, from nests of different locations in the block, twice a month. In this case, the cross of birds and their productive age were taken into account. For lab testing of the studied indicators, for which the opening of the egg was not required, in particular, weight and density, 50 pcs were selected; to determine quality indicators, on the contrary, requiring opening of eggs (mass of egg white and yolk, shell thickness) – 20 pieces; for determination of provitamin A, retinol and acid number index – 10 eggs. Our laboratory studies have found that with an increase in the productive age of laying hens, the weight of the hatching eggs themselves also increases, regardless of their belonging to the cross of meat hens. The hatching egg obtained from laying hens of the “Cobb” cross at all age periods differed in weight by more than 2 % from the same studied indicator of the eggs, which were selected from hens of the “Ross” cross. The shell thickness of the eggs studied in the laboratory corresponded to the reference indicators, regardless of the belonging to the cross and the age of the breeding bird. The density of the egg whites and yolk was generally slightly below the industry standard and generally met its requirements. The content of pigments in its yolk part met the requirements of the standard. Vitamin A content exceeded the minimum standard requirements.