使用线程移动PictureBox位置

我正在创建一个鸡蛋掉落的捕捉游戏。在Panel子类中，我有如下代码

public void startGame()
    {
        Thread t = new Thread(new ThreadStart(game));
        t.Start();
    }
private void game()
    {
        bool run = true;
        int level = 1;
        while (run)
        {
            Egg egg = dropper.selectEgg();
            int speed = dropper.getSpeed(level);
            if (this.InvokeRequired)
            {
                this.Invoke(new MethodInvoker(delegate { 
                    this.Controls.Add(egg);
                    egg.setInitialLocation(dropper.selectPosition());
                    int x = egg.Location.X;
                    int y = egg.Location.Y;
                    while (y <= 1000)
                    {
                        egg.setCurrentLocation(x, dropper.drop(egg, speed));
                        y = egg.Location.Y;
                    }
                }));
            }
            else
            {
                this.Controls.Add(egg);
                egg.setInitialLocation(dropper.selectPosition());
                int x = egg.Location.X;
                int y = egg.Location.Y;
                while (y <= 1000)
                {
                    egg.setCurrentLocation(x, dropper.drop(egg, speed));
                    y = egg.Location.Y;
                }
            }
            Thread.Sleep(3000);
        }
    }

Egg是PictureBox的一个子类，我想改变它在循环上的位置，使它看起来像鸡蛋正在掉落。我用这个方法使用EggDropper子类:

public int drop(Egg egg, int speed)
    {
        int y = egg.Location.Y;
        y += speed;
        return y;
    }

但不知怎么的，我没有看到任何蛋的物体掉下来。我猜这是访问PictureBox子类的线程的问题?但是我在网上似乎找不到任何解决办法。

非常感谢。