diff --git a/internal/modules/production/chickins/repositories/project_chickin.repository.go b/internal/modules/production/chickins/repositories/project_chickin.repository.go
index 43cafaac..ffdae20b 100644
--- a/internal/modules/production/chickins/repositories/project_chickin.repository.go
+++ b/internal/modules/production/chickins/repositories/project_chickin.repository.go
@@ -16,6 +16,7 @@ type ProjectChickinRepository interface {
 	GetPendingByProjectFlockKandangID(ctx context.Context, projectFlockKandangID uint) ([]entity.ProjectChickin, error)
 	GetTotalPendingUsageQtyByProjectFlockKandangID(ctx context.Context, projectFlockKandangID uint) (float64, error)
 	GetTotalChickinQtyByProjectFlockID(ctx context.Context, projectFlockID uint) (float64, error)
+	GetByProjectFlockKandangIDForUpdate(ctx context.Context, projectFlockKandangID uint) ([]entity.ProjectChickin, error)
 }
 
 type ChickinRepositoryImpl struct {
@@ -64,6 +65,20 @@ func (r *ChickinRepositoryImpl) GetByProjectFlockKandangID(ctx context.Context,
 	return chickins, nil
 }
 
+// GetByProjectFlockKandangIDForUpdate locks chickin rows to prevent race condition
+func (r *ChickinRepositoryImpl) GetByProjectFlockKandangIDForUpdate(ctx context.Context, projectFlockKandangID uint) ([]entity.ProjectChickin, error) {
+	var chickins []entity.ProjectChickin
+	err := r.db.WithContext(ctx).
+		Where("project_flock_kandang_id = ?", projectFlockKandangID).
+		Order("created_at DESC").
+		Find(&chickins).
+		Error
+	if err != nil {
+		return nil, err
+	}
+	return chickins, nil
+}
+
 func (r *ChickinRepositoryImpl) GetPendingByProjectFlockKandangID(ctx context.Context, projectFlockKandangID uint) ([]entity.ProjectChickin, error) {
 	var chickins []entity.ProjectChickin
 	err := r.db.WithContext(ctx).
diff --git a/internal/modules/production/chickins/services/chickin.service.go b/internal/modules/production/chickins/services/chickin.service.go
index 871c8fce..5ba665ca 100644
--- a/internal/modules/production/chickins/services/chickin.service.go
+++ b/internal/modules/production/chickins/services/chickin.service.go
@@ -137,6 +137,7 @@ func (s *chickinService) CreateOne(c *fiber.Ctx, req *validation.Create) ([]enti
 	if err != nil {
 		return nil, err
 	}
+
 	newChikins := make([]*entity.ProjectChickin, 0)
 	chickinQtyMap := make(map[uint]float64)
 
@@ -151,8 +152,8 @@ func (s *chickinService) CreateOne(c *fiber.Ctx, req *validation.Create) ([]enti
 			return nil, fiber.NewError(fiber.StatusBadRequest, fmt.Sprintf("Product warehouse %d is not bound to kandang's warehouse", chickinReq.ProductWarehouseId))
 		}
 
-		if productWarehouse.ProjectFlockKandangId == nil || *productWarehouse.ProjectFlockKandangId != req.ProjectFlockKandangId {
-			return nil, fiber.NewError(fiber.StatusBadRequest, fmt.Sprintf("Product warehouse %d is not attached to project_flock_kandang %d. Only product warehouses with matching project_flock_kandang_id can be chickin-ed", chickinReq.ProductWarehouseId, req.ProjectFlockKandangId))
+		if productWarehouse.ProjectFlockKandangId != nil && *productWarehouse.ProjectFlockKandangId != req.ProjectFlockKandangId {
+			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))
 		}
 
 		chickinDate, err := utils.ParseDateString(chickinReq.ChickInDate)
@@ -160,11 +161,6 @@ func (s *chickinService) CreateOne(c *fiber.Ctx, req *validation.Create) ([]enti
 			return nil, fiber.NewError(fiber.StatusBadRequest, fmt.Sprintf("Invalid ChickInDate format for product warehouse %d", chickinReq.ProductWarehouseId))
 		}
 
-		availableQty := productWarehouse.Quantity
-		if availableQty <= 0 {
-			return nil, fiber.NewError(fiber.StatusBadRequest, fmt.Sprintf("No available stock in product warehouse %d for chickin", chickinReq.ProductWarehouseId))
-		}
-
 		newChickin := &entity.ProjectChickin{
 			ProjectFlockKandangId: req.ProjectFlockKandangId,
 			ChickInDate:           chickinDate,
@@ -176,22 +172,46 @@ func (s *chickinService) CreateOne(c *fiber.Ctx, req *validation.Create) ([]enti
 		}
 
 		newChikins = append(newChikins, newChickin)
-		chickinQtyMap[uint(idx)] = availableQty
+		chickinQtyMap[uint(idx)] = productWarehouse.Quantity
 	}
 
 	if len(newChikins) == 0 {
 		return nil, fiber.NewError(fiber.StatusBadRequest, "No chickins to create")
 	}
 
-	existingChikins, err := s.Repository.GetByProjectFlockKandangID(c.Context(), req.ProjectFlockKandangId)
-	if err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {
-		return nil, fiber.NewError(fiber.StatusInternalServerError, "Failed to check existing chickins")
-	}
-
-	isFirstTime := len(existingChikins) == 0
-
 	err = s.Repository.DB().WithContext(c.Context()).Transaction(func(dbTransaction *gorm.DB) error {
 
+		repositoryTx := repository.NewChickinRepository(dbTransaction)
+		existingChikins, err := repositoryTx.GetByProjectFlockKandangIDForUpdate(c.Context(), req.ProjectFlockKandangId)
+		if err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {
+			return fiber.NewError(fiber.StatusInternalServerError, "Failed to check existing chickins")
+		}
+
+		isFirstTime := len(existingChikins) == 0
+
+		pendingQtyMap := make(map[uint]float64)
+		for _, existingChickin := range existingChikins {
+			if existingChickin.PendingUsageQty > 0 {
+				pendingQtyMap[existingChickin.ProductWarehouseId] += existingChickin.PendingUsageQty
+			}
+		}
+
+		for idx, chickin := range newChikins {
+			pendingQty := pendingQtyMap[chickin.ProductWarehouseId]
+			desiredQty := chickinQtyMap[uint(idx)]
+
+			availableQty := desiredQty - pendingQty
+			if availableQty < 0 {
+				availableQty = 0
+			}
+
+			if availableQty <= 0 {
+				return fiber.NewError(fiber.StatusBadRequest, fmt.Sprintf("No available stock in product warehouse %d for chickin. Warehouse: %.0f, Pending: %.0f, Available: %.0f", chickin.ProductWarehouseId, desiredQty, pendingQty, availableQty))
+			}
+
+			chickinQtyMap[uint(idx)] = availableQty
+		}
+
 		approvalSvcTx := commonSvc.NewApprovalService(commonRepo.NewApprovalRepository(dbTransaction))
 
 		if err := s.Repository.WithTx(dbTransaction).CreateMany(c.Context(), newChikins, nil); err != nil {
diff --git a/internal/modules/production/project-flock-kandangs/services/project_flock_kandang.service.go b/internal/modules/production/project-flock-kandangs/services/project_flock_kandang.service.go
index 66fee8ce..6176daeb 100644
--- a/internal/modules/production/project-flock-kandangs/services/project_flock_kandang.service.go
+++ b/internal/modules/production/project-flock-kandangs/services/project_flock_kandang.service.go
@@ -191,7 +191,7 @@ func (s projectFlockKandangService) getAvailableQuantities(c *fiber.Ctx, project
 	result := make(map[uint]float64)
 	for _, pw := range products {
 
-		if pw.ProjectFlockKandangId != nil && *pw.ProjectFlockKandangId == projectFlockKandang.Id {
+		if pw.ProjectFlockKandangId == nil || *pw.ProjectFlockKandangId == projectFlockKandang.Id {
 			availableQty, err := s.calculateAvailableQuantityForProductWarehouse(c, projectFlockKandang, &pw)
 			if err != nil {
 				s.Log.Warnf("Failed to calculate available quantity for product warehouse %d: %v", pw.Id, err)