Physical characteristics of chicken eggs in relation to their hatchability and chick weight

Egg weight, egg volume, shell surface area, egg specific gravity, maximum breadth to length ratio, and the ratio of egg weight to shell surface area were chosen for investigating of their influence on egg hatchability. To estimate the relationship between the hatchability and quantitative factors of each investigated parameter, a ranking system was performed. All measured and calculated egg parameters were divided into three groups: (1) the values were within the average value ± standard deviation; (2) the values less than the 1st group; (3) the values more than the 1st group. The small eggs were more successful at hatching. The hatchability of the ‘round-shaped’ eggs was higher than for the others. The analysis showed that approximately 30 % of non-hatched eggs had the following combination of physical characters: egg density considers to the 2nd group, while egg weight and/or volume belongs to the 1st or the 3rd one. Only 5.8 % of the fit eggs had such combination of physical parameters. The non-hatched eggs, which values of the egg weight to surface area ratio belong to the 2nd group, and the weight and/or volume to the 1st one, constitute 17 %, whilst the analogical combination for the fit eggs was equal to 3 %. The probability of the success of hatching can be estimated by the defined multiparametric logit function.

For the best prediction of chick weight by the data of egg physical characters the quadratic type of the equation with three basic egg parameters (weight, volume and surface area) should be used. The coefficient of determination varied from R2 = 0.26 to 0.63, depending on the hen’s strain data.