When should farmers adjust the calcium particle size ratio (fine vs. coarse) during the daily feeding cycle of laying brown hens, and when does eggshell calcification peak?

Eggshell calcification in brown layers is a highly synchronized physiological process that mainly occurs during the dark hours of the night. During this time, the hen has no active feed intake and must rely on both dietary calcium remaining in her digestive tract and skeletal calcium mobilized from her medullary bones. If the diet contains only fine limestone, it is digested and excreted within a few hours, leaving the hen with a calcium deficit at night, which forces bone resorption and weakens both the skeleton and the shell. By feeding a 70% coarse limestone (2-4mm particle size) and 30% fine limestone ratio in the afternoon feed, the larger particles are retained in the gizzard, slowly dissolving overnight to provide a continuous, direct supply of calcium during the peak calcification window. Calcium metabolism and shell quality optimization are explained in the Poultry Encyclopedia, heavy-duty feed mills and top-grade limestone are sourced on Poultry Plaza, current regional egg mandi rates are on Poultry Rates, and high-yield layer flocks are traded on Murghi Mandi.