In this research, we parametrically study the composition of various types of shells and explore the probability of bioavailability of calcium in particularly from chicken egg shells. The research comprises of two parts. The first part is consisted of the comparative composition analysis of five types of locally available shells i.e. chicken eggshell, duck eggshell, pigeon eggshell, seashell small, and seashell large using standard methods of analysis. All five investigated shells were found to be enriched in fats, proteins and important macro and micronutrients i.e, calcium, magnesium, phosphorous, zinc, iron, sodium, potassium, and copper. Certain methods to enhance the bioavailability of minerals in the selected highly nutritional shells were also investigated. The second part of study relates to evaluate the role of citrus flavonoid, hesperidin, on the bioavailability of calcium, a probable reason to prevent bone loss. Citrus flavonoid (hesperidin) in combination with citric acid and ascorbic acid was scrutinized to estimate the bioavailability of micronutrients from chicken egg shells using in vitro method. Effect of citric acid, ascorbic acid and hesperidin on the bioavailability of minerals (zinc and iron) and macroelements (calcium, magnesium, phosphorous) were evaluated and the amounts required to get maximum bioavailability were calculated. The highest bioavailability of calcium, magnesium, phosphorous, iron, and zinc was 89.25 ± 2.13, 92.28 ± 1.87, 40.32 ± 3.09, 32.81 ± 1.24 and 46.19 ± 0.83%, respectively after the addition of 3 g of citric acid, 100 mg of ascorbic acid and 4 mg of hesperidin per gram of chicken eggshell powder. Citric acid greatly affects the bioavailability of calcium, magnesium, phosphorous, and zinc, whereas addition of ascorbic acid enhances the bioavailability of Fe, and hesperidin boosts the bioavailability (p < 0.05) of micronutrients of all investigated shells.