diff --git a/src/components/PigBatchList.vue b/src/components/PigBatchList.vue
index a6bcea7f..2e932ca9 100644
--- a/src/components/PigBatchList.vue
+++ b/src/components/PigBatchList.vue
@@ -129,9 +129,12 @@ export default {
         // Create a map for quick lookup of house names by ID
         const houseMap = new Map(houses.map(house => [house.id, house.name]));
 
-        this.availablePens = pens.map(pen => ({
+        // Filter for pens that are not assigned to any batch
+        const unassignedPens = pens.filter(pen => !pen.pig_batch_id);
+
+        this.availablePens = unassignedPens.map(pen => ({
           id: pen.id,
-          label: `${pen.pen_number}(${houseMap.get(pen.house_id) || '未知猪舍'})` // Changed format here
+          label: `${pen.pen_number} (${houseMap.get(pen.house_id) || '未知猪舍'})`
         }));
       } catch (error) {
         console.error("Error fetching pens or houses:", error);