When does the economic return on extending a brown layer's production cycle beyond 80 weeks peak, and when does feed conversion become unprofitable?

Extending a brown layer flock's production cycle beyond the standard 80 weeks up to 90 or 100 weeks is an advanced financial decision. The economic return peaks during periods when chick replacement prices are extremely high and market egg rates are exceptionally strong, making it highly lucrative to squeeze more eggs out of the current flock. However, this extension becomes highly unprofitable if the flock's feed conversion ratio (FCR) exceeds 2.6 (or feed intake per egg exceeds 135 grams) due to declining egg numbers (below 65% lay intensity) and poor gut absorption. Additionally, the rate of unmarketable cracked and soft-shelled eggs late in lay must be kept under 3% using specialized feed additives. Life-cycle economics are detailed in the Poultry Encyclopedia, premium organic calcium-binders and amino acids are sold on Poultry Plaza, live mandi egg and feed rates are on Poultry Rates, and long-cycle laying flocks are listed on Murghi Mandi.