diff --git a/internal/modules/production/chickins/services/chickin.service.go b/internal/modules/production/chickins/services/chickin.service.go
index 3ff5d8d9..8c896aef 100644
--- a/internal/modules/production/chickins/services/chickin.service.go
+++ b/internal/modules/production/chickins/services/chickin.service.go
@@ -156,6 +156,25 @@ func (s *chickinService) CreateOne(c *fiber.Ctx, req *validation.Create) ([]enti
 			return nil, fiber.NewError(fiber.StatusBadRequest, fmt.Sprintf("Product warehouse %d belongs to different flock. Only product warehouses with project_flock_kandang_id = NULL or = %d can be used", chickinReq.ProductWarehouseId, req.ProjectFlockKandangId))
 		}
 
+		// CRITICAL: Validate product category based on flock category
+		// GROWING: Input DOC, Output PULLET
+		// LAYING: Input PULLET, Output LAYER
+		if productWarehouse.Product.Id != 0 {
+			productCategoryCode := productWarehouse.Product.ProductCategory.Code
+			var allowedCategory string
+			if projectFlockKandang.ProjectFlock.Category == string(utils.ProjectFlockCategoryGrowing) {
+				allowedCategory = "DOC"
+			} else if projectFlockKandang.ProjectFlock.Category == string(utils.ProjectFlockCategoryLaying) {
+				allowedCategory = "PULLET"
+			} else {
+				return nil, fmt.Errorf("invalid flock category for chickin")
+			}
+
+			if productCategoryCode != allowedCategory {
+				return nil, fmt.Errorf("product warehouse %d cannot be used for %s chickin. Only %s products can be used as input (current: %s)", chickinReq.ProductWarehouseId, projectFlockKandang.ProjectFlock.Category, allowedCategory, productCategoryCode)
+			}
+		}
+
 		chickinDate, err := utils.ParseDateString(chickinReq.ChickInDate)
 		if err != nil {
 			return nil, fiber.NewError(fiber.StatusBadRequest, fmt.Sprintf("Invalid ChickInDate format for product warehouse %d", chickinReq.ProductWarehouseId))