I think it means using a nesting box that takes up almost the entire space in a tub. I'm trying it now with a corn and hog.
Using Coco peat ( kind you soak to boost it) and leaving some original bedding(in my case aspen) around the nesting box. Water dish outside the box. Both seem to prefer the coco nest box to move around in. The hog is buried underneath. Can't see her unless I lift the tub. Using a medium tub in an ARS rack.
Unless I hear otherwise, this is it. mike