Great informative article! I am guilty of giving broodies flat surfaces (plastic dog crates) to incubate their eggs in. Early on when lots of hens began to go broody, I did notice the plastic bottom was too slick for them to keep their legs from splaying out to the side, so I started putting rectangular, low-sided cardboard boxes inside the plastic crates to decrease the nest size. This has worked sufficiently, but the surface is still flat, and your way seems so much better. Especially since my soil is very sandy, and so very easy for a hen to make a perfect nest area. Broodies are nearly done hatching this year, but next year I will let them do it your way!