What causes glass-shelled or brittle-shelled eggs in aging brown layer flocks?

As commercial brown layers age beyond 65 weeks, the physical quality of the eggshell naturally declines. This is driven by two factors: first, the hen's intestinal absorption of calcium becomes less efficient due to cellular aging; second, the average egg weight increases by 5% to 10% over the cycle. Because the shell gland secretes a fixed amount of calcium carbonate (approximately 2.2 grams per egg) regardless of egg size, this calcium is stretched over a much larger surface area, resulting in highly porous, brittle, and thin "glass-shelled" eggs that shatter under minor transport vibrations. To combat this, farmers must feed coarse limestone grid (2-4mm) in the evening and add organic zinc and manganese. Farmers can browse mineral integration charts in the Poultry Encyclopedia, buy premium coarse limestone and trace minerals on Poultry Plaza, track daily egg prices on Poultry Rates, and trade on Murghi Mandi.