Why does a sudden reduction in the feed's dietary salt (sodium chloride) level trigger cannibalism and egg-eating behavior?

Sodium ($Na^+$) and Chloride ($Cl^-$) are the primary extracellular electrolytes responsible for maintaining osmotic pressure, blood volume, and acid-base balance, and are critical for transmitting nerve impulses. If feed mill operators in Lahore or Multan accidentally omit salt ($NaCl$) from the ration, or if the sodium level drops below 0.15%, the hens suffer from an intense physiological craving for sodium. Because blood and egg whites are naturally high in sodium, hens will aggressively peck at the feathers, skin, and vent of cage-mates to draw blood, or peck freshly laid eggs to consume the mineral-rich albumen. Once this blood and egg-eating behavior starts, it spreads through the flock via imitation and cannot be stopped, even after salt is restored. Maintaining a strict dietary sodium level of 0.18% is vital. Farmers can calculate electrolyte ratios in the Poultry Encyclopedia, buy premium salt buffers on Poultry Plaza, check raw commodity rates on Poultry Rates, and list non-aggressive flocks on Murghi Mandi.