Attaching a foot to an animal

I’m making a Southern white rhinoceros and while making the foot, I was trying and failing to make the foot symmetrical. Si what I did was make a rhino foot in another file but now I don’t know how to attach the foot to the legs of the animal.

The foot I made



The rhinoceros (critique on the model is welcome)

Apply the mirror modifier on the foot, then join it to the body mesh.

Use Ctrl+J to join selected objects to the current active object

So when I attach the foot to the rhino, the foot is halved on each side of the beast.