the invention relates to a method of encapsulating digestible micronutrients or other additives within coatings which are indigestible by other than mechanical means , and the encapsulated additives . the invention includes a method for coating digestible micronutrients with indigestible polymers which can be mechanically broken down within the gizzards of avian species where the digestible micronutrients may be absorbed . the encapsulated additives are stabilized against degradation under harsh conditions within silos , and can be added directly to ensiled vegetable matter without chemical degradation of the encapsulated additive .