I use a 4x4 x pen. I put down a half sheet of plywood and covered that with some vinyl flooring. The x pen sits right around the edge of the wood.
I have it divided into 3 areas. A sleeping area, a play area and a potty area. They learn at a very early age, 3 to 4 weeks to leave the sleeping area and go to the pee pad to potty. They will occasionally pee in the play area, but at 6 weeks they do not pee in their bed.
005 (972 x 648).jpg 006 (648 x 972).jpg