Why does an overload of dietary magnesium in drinking water cause severe watery droppings and thin eggshells in brown layers?

Drinking water quality is frequently overlooked on commercial farms, yet it serves as a major source of dissolved minerals. In arid regions of Punjab and Sindh, deep well water often carries high levels of magnesium carbonate ($MgCO_3$) or magnesium sulfate ($MgSO_4$). Magnesium and calcium share the same divalent ion transport channels in the intestinal mucosa. If drinking water magnesium levels exceed 125 ppm, magnesium directly competes with calcium for these active transport proteins, severely reducing dietary calcium absorption and leading to thin, brittle shells. Furthermore, unabsorbed magnesium ions in the intestinal tract act as a strong osmotic laxative, drawing massive volumes of water from the blood into the intestinal lumen to equalize osmotic pressure. This results in chronic, severe watery diarrhea (osmotic diarrhea), causing wet litter, high ammonia, and dirty, manure-stained eggs. Installing reverse osmosis (RO) water purification is mandatory. Farmers can consult mineral water standards in the Poultry Encyclopedia, buy RO systems and water acidifiers on Poultry Plaza, check daily egg prices on Poultry Rates, and trade premium brown eggs on Murghi Mandi.