Scientific experiments on determination of the optimal doses kizelgur for import substitution of shells in poultry diets was realized in the conditions of the Republic of Belarusby an example of 4 groups of laying hens of Khajseks korichnevyj cross. Hens of the first (controlled) group were given full ration applied at the tested poultry farm which included 5% of shells. Hens of the other three experimental groups were given complete feedstuffs with inclusion of mineral feed kizelgur: hens of the second group – in dose 2% out of dry matter mass; third group - 3%; for the fourth group - 4%. The research results showed that application of mineral feed additive kizelgur increased hen productivity in experimental groups on 2,8%; 5,9%; 7,2%, respectively. In the experimental groups there was an increasing of egg yields on 2,8%; 5,9%; 7,2%, respectively. The best indexes of poultry livability were stated in the third group (on 5,5% higher than in control). The similar tendency was stated in course of analysis of egg weight, shell thickness and calcium content of shell. Kizelgur application led to increasing of egg mass in tested groups: on 0,46% (2 group), 1,6% (3 group) and 2,4 % (4 group). At the age of 340 days shell thickness in experimental groups was on higher 3,3% (2 group), 0,7% (3 group) and 8,7 % (4 group) than in control. The analyzed additive increased the natural resistance of hens that was proved by indexes of bacterial growth-inhibitory activity of blood serum and lysozyme activity. There noted tendency of total protein increasing. Studying of immunological indexes showed that they were the most evident in the fourth experimental group

Into the programme hen selection of Belarus Autoseksnyj cross there was introduced the indeks of the so-called quality of eggs which is defined by removal defective on quality of a shell of eggs in 30 and 52-week age. The size of variability of an indicator of 16,0-25,4% and hehtability 0,3-0,4 allows to lead selection on increase in an exit of qualitative eggs. Influence on quality of eggs with defects of a shell of age of hens, intensity eggs, weights of eggs, a linear accessory is established