dnd 5e – What options do my players have to hide their cart while they enter a dungeon?

I am running my first DnD 5e campaign for a completely new party and we are doing Lost Mines of Phandelver. My group has just decided that they want to go to Cragmaw's hiding place after the ambush and they, through much struggle, managed to take the cart with them. After dealing with the goblins outside the cave, they are now planning to go to hiding, but I think they have forgotten their car, we stopped the session here.

Now, since my players are all new and in fact they have forgotten their cart, I plan to ask them to think about it. I suppose they could decide to leave the car outside, or cover it with the bushes, but what about the oxen? If you leave it somewhere where you are obviously going to see it, I would like this to have some consequence.

To the question then, what can I do so that my players, if anything, do something with the cart and the oxen?

If they do not do something to prevent the goblins from finding it, what is reasonable for the goblins to do?