diff --git a/internal/app/controller/management/pig_farm_controller.go b/internal/app/controller/management/pig_farm_controller.go
index d31ef31..e787254 100644
--- a/internal/app/controller/management/pig_farm_controller.go
+++ b/internal/app/controller/management/pig_farm_controller.go
@@ -239,12 +239,11 @@ func (c *PigFarmController) CreatePen(ctx *gin.Context) {
 	}
 
 	resp := dto.PenResponse{
-		ID:         pen.ID,
-		PenNumber:  pen.PenNumber,
-		HouseID:    pen.HouseID,
-		Capacity:   pen.Capacity,
-		Status:     pen.Status,
-		PigBatchID: *pen.PigBatchID,
+		ID:        pen.ID,
+		PenNumber: pen.PenNumber,
+		HouseID:   pen.HouseID,
+		Capacity:  pen.Capacity,
+		Status:    pen.Status,
 	}
 	controller.SendSuccessWithAudit(ctx, controller.CodeCreated, "创建成功", resp, action, "创建成功", resp)
 }
@@ -278,12 +277,14 @@ func (c *PigFarmController) GetPen(ctx *gin.Context) {
 	}
 
 	resp := dto.PenResponse{
-		ID:         pen.ID,
-		PenNumber:  pen.PenNumber,
-		HouseID:    pen.HouseID,
-		Capacity:   pen.Capacity,
-		Status:     pen.Status,
-		PigBatchID: *pen.PigBatchID,
+		ID:        pen.ID,
+		PenNumber: pen.PenNumber,
+		HouseID:   pen.HouseID,
+		Capacity:  pen.Capacity,
+		Status:    pen.Status,
+	}
+	if pen.PigBatchID != nil {
+		resp.PigBatchID = *pen.PigBatchID
 	}
 	controller.SendSuccessWithAudit(ctx, controller.CodeSuccess, "获取成功", resp, action, "获取成功", resp)
 }
@@ -307,14 +308,17 @@ func (c *PigFarmController) ListPens(ctx *gin.Context) {
 
 	var resp []dto.PenResponse
 	for _, pen := range pens {
-		resp = append(resp, dto.PenResponse{
-			ID:         pen.ID,
-			PenNumber:  pen.PenNumber,
-			HouseID:    pen.HouseID,
-			Capacity:   pen.Capacity,
-			Status:     pen.Status,
-			PigBatchID: *pen.PigBatchID,
-		})
+		res := dto.PenResponse{
+			ID:        pen.ID,
+			PenNumber: pen.PenNumber,
+			HouseID:   pen.HouseID,
+			Capacity:  pen.Capacity,
+			Status:    pen.Status,
+		}
+		if pen.PigBatchID != nil {
+			res.PigBatchID = *pen.PigBatchID
+		}
+		resp = append(resp, res)
 	}
 
 	controller.SendSuccessWithAudit(ctx, controller.CodeSuccess, "获取成功", resp, action, "获取成功", resp)
@@ -358,12 +362,14 @@ func (c *PigFarmController) UpdatePen(ctx *gin.Context) {
 	}
 
 	resp := dto.PenResponse{
-		ID:         pen.ID,
-		PenNumber:  pen.PenNumber,
-		HouseID:    pen.HouseID,
-		Capacity:   pen.Capacity,
-		Status:     pen.Status,
-		PigBatchID: *pen.PigBatchID,
+		ID:        pen.ID,
+		PenNumber: pen.PenNumber,
+		HouseID:   pen.HouseID,
+		Capacity:  pen.Capacity,
+		Status:    pen.Status,
+	}
+	if pen.PigBatchID != nil {
+		resp.PigBatchID = *pen.PigBatchID
 	}
 	controller.SendSuccessWithAudit(ctx, controller.CodeSuccess, "更新成功", resp, action, "更新成功", resp)
 }