Well, decomposing manure/compost naturally generates heat because of the bacterial action and chemical reactions. That’s why you can pack it around the roots of a warm weather plant to ward off frost damage.
That fact is not lost on this bird.
"In Australia, there is a bird called the Brush-turkey (Alectura lathami) that builds compost piles to incubate the eggs so that they won't have to sit on them! They build mounds of decomposing vegetation, and the heat produced by the microbial decay maintains the eggs at about 33°C (92°F), 15°C warmer than the ambient air temperature."