Poultry diseases remain one of the major threats to poultry production worldwide, and chicken diseases have become one of the problems that are very detrimental to chicken farmers. Therefore, it is vital to give due attention because of its impact on the health and quality of chicken production. To solve the problem, a knowledge-based system can be a powerful tool with vast potential in alleviating agricultural and medical problems. This study aims to develop a knowledge base system for diagnosing, preventing, and managing predominant chicken diseases. The Design science research method was used to develop the prototype system. The acquired knowledge was modelled and represented using a decision tree and production rules (If-Then-Action). A backward chaining algorithm was used in this study. The prototype system was tested and evaluated, including both performance of the prototype system and user acceptance. The performance comparison parameters such as precision, recall, and F-measure were used to measure the accuracy of the prototype system, and the performance was 83%. The proposed system can assist the experts in identifying the type of disease based on the chickens' symptoms. This study is significant in providing system-based help for identifying predominant chicken diseases based on their symptoms using different techniques.