I thought it's general chemisty, when calories are "burned", heat is given off (chemical energy to kinetic energy), it doesn't matter what's burning, fat, calories, gasoline, Eli Manning's throwing hand...KLG Please post it, I'd love to read it, maybe what I have is outdated. Just to clear it up, I wasn't saying that they create enough heat to incubate without heat or anything like that, just that I had read that they do twitch to help the incubation process which generates heat, not instead of basking and returing to the eggs.