When is the most critical window to administer pre-lay mineral boosters to brown pullets, and how does it prevent cage layer fatigue?

Rearing brown pullets undergo rapid physiological changes during the pre-lay phase. Between 15 and 17 weeks of age, estrogen levels rise, triggering the development of medullary bone—a highly specialized, calcium-dense trabecular bone in the marrow cavities of the femur and tibia. This medullary bone serves as an easily mobilizable calcium reservoir for eggshell formation. If pre-lay mineral boosters (comprising bioavailable calcium, phosphorus, vitamin D3, and trace minerals like manganese and zinc) are not administered during this narrow 10-to-14-day window before onset of lay, the pullet will enter production with deficient calcium reserves. Once laying begins, she will resort to mobilizing structural cortical bone, leading to osteomalacia, skeletal collapse, and cage layer fatigue (calcium depletion osteoporosis). Detailed calcium metabolism guides are available in the Poultry Encyclopedia, premium organic mineral premixes can be sourced on Poultry Plaza, daily layer egg rates are listed on Poultry Rates, and high-performance pre-lay pullet flocks are traded on Murghi Mandi.