Inventory management and pricing are critical topics in optimizing performance within inventory control planning and supply chain management, directly impacting the profitability and productivity of organizations. This paper presents an inventory management and pricing model for growing items within a two-level supply chain consisting of a supplier and a distributor. The model is designed under the assumption that the distributor's demand is a linear and non-increasing function of the product's selling price. The primary objective of this research is to propose an optimized approach to inventory management and pricing to maximize profit and enhance coordination within the supply chain. Additionally, the paper introduces the prepayment strategy as an effective method to improve supply chain coordination and performance.

The proposed model is analyzed in two distinct scenarios: non-integrated and integrated. In the non-integrated scenario, the supplier and the distributor make decisions independently, whereas, in the integrated scenario, decisions are made collaboratively. The mathematical model developed in this study is designed to maximize the total profit of the supply chain. In this model, the supplier purchases newborn animals and raises them over a specified period until they reach maturity, after which they are sold. Mathematical optimization techniques are employed to solve the problem and identify the optimal solution. To evaluate the efficiency of the models and analyze the sensitivity of various parameters, a numerical example is provided.

The results of the study indicate that changes in certain parameters have minimal impact on the length of the supplier's rearing period. Specifically, the rearing period is more dependent on production and rearing processes than on pricing and other economic parameters. On the other hand, changes in unit purchasing costs at each level of the supply chain significantly affect the final profit. These changes can lead to a substantial increase or decrease in the final profit through adjustments in pricing and purchasing strategies. These findings highlight the importance of cost management and pricing optimization, which can significantly influence supply chain performance. Furthermore, the results demonstrate that integrated models outperform non-integrated models, particularly when the prepayment strategy is utilized to enhance supply chain coordination. In integrated models, collaborative decision-making between the supplier and the distributor improves coordination, reduces costs, and ultimately increases the final profit.

The conclusion of this research underscores that effective coordination within the supply chain, particularly through integration and the use of prepayment strategies, can positively impact profitability and overall supply chain performance. Additionally, attention to unit purchasing costs and the optimization of pricing and purchasing processes are essential for maximizing profit at each level of the supply chain. This study demonstrates that integrated models serve as effective tools for improving inventory management and pricing decision-making within supply chains. By fostering collaboration and strategic alignment between supply chain partners, organizations can achieve greater efficiency and profitability. The findings also emphasize the need for further research into the application of prepayment strategies and integrated models in diverse supply chain contexts to validate their effectiveness across different industries and operational environments. Overall, this research contributes to the growing body of knowledge on supply chain optimization by providing actionable insights into the interplay between inventory management, pricing strategies, and supply chain coordination.