Handling inventory post-maturity presents challenges for supply chain revenue. This study investigates advance payment options through finite installments to improve inventory costs. It assesses the effects of partial payments on inventory management and livestock sales via the EGQ model, while considering item deterioration over time. The methodology includes screening livestock to discard weaker items before maturation for sale. Retailers can opt for pre-payments in instalments which, when analyzed using the gradient method, suggest that fewer installment options may lead to cost reductions. The process begins with receiving young items, followed by a screening phase to improve sale quality. Deterioration risks are considered, along with the financial strategy of paying in advance before restocking. The total cost for the system is derived analytically and optimized through gradient techniques, focusing on maximum inventory levels post-management and purchase quantities. The findings indicate that minimizing pre-installment payments can further decrease costs, and managing feeding expenses effectively can lessen overall expenditures. The research provides managerial insights and demonstrates practical parameter applications.