Four mineral-org. feed additives were produced of humic materials, herbs, alfalfa and glycerol by using exothermic reactions of CaO hydration and administred to laying hens. The homogenized egg mass was studied for content of elements by flame at. absorption spectroscopy. The contents of Ca, R Mn, Cu, Fe and Zn increased mainly in the eggs when feed additives were administred, while Mg and Se contents did not change. The concns. of Cd and Pb changed irregularly. The lowest Pb concns. were found for the humic-herb additives.