Influence of the mass of chicken eggs laid on incubation on hatchability and safety of chickens

For incubation, it is allowed to use eggs obtained from clinically healthy birds from a farm that is free from infectious diseases. Eggs from hens of egg breeds elder younger than 7 months, meat-and-egg breeds elder than 8 months, and meat breeds elder than 9 months are accepted for incubation. The quality of eggs is assessed based on a set of characteristics, including weight, shape, density, ratio of the mass of the egg's components, height of the white and yolk, and thickness and strength of the shell.The studies were conducted to investigate the effect of the mass of chicken eggs used for incubation on the live weight, average daily growth, and survival rate of chicks before slaughter. As a result of the biological quality control of the incubation eggs, it was found that the lowest number of unfertilized eggs was in the second group, where the egg mass was the highest one. (65g). The amount of incubation waste was the lowest in the 3rd experimental group with an egg weight of 60 g, at 18.6%, which is 3.5% and 0.7% lower than in the first and second groups, respectively. The highest number of viable chicks was obtained in the 3rd group from eggs weighing 60 g, at 81.4%. The weight of day-old chicks was in direct proportion to the size of the eggs when they were placed in the incubator: the smaller the eggs, the lighter the chicks. Chickens hatched from the large eggs had the highest average daily growth rates of 48.9 g, while chickens hatched from the small eggs had the lowest average daily growth rates of 47.2 g. At the same time, the relative weight of chickens hatched from smaller eggs was higher, indicating a slight advantage in the development of their embryos and a better utilization of the nutrients in the eggs.