How to use compound colliders for humanoid avatar?

Hi guys!

I am trying to add colliders to an avatar. As it's an humanoid, I have several children objects ("joints"), so I want to add a collider for each part of the body (eg. one box collider for each foot, one for each lower leg, etc).

So far, I've tryied the following:

• Create an empty child game object in the left foot joint game object.

• Add a box collider component to that empty child.

• Resize and move the collider.

What I don't understand is, as soon as I move/resize the collider, the parent's (left foot joint) transform (also "grand-parents'", etc.) appear to have moved BUT their values remain the same. In addition, as soon as I remove the child gameobject (the one that contains the box collider) the transforms return to their initial state.

I'm not sure if I have explained myself so I've attached two screenshots. In the first one you can see the original position of the transforms; in the second one you can see how the transforms have moved after adding and editing the collider.