There was a big debate on a UK forum as to whether a broody's body temp actually rises while incubating eggs. I would think it's possible, I mean, a woman's body temp rises during ovulation. I know it's not the same, but it's not unheard of for body temp to rise...especially having to do with reproduction. I mentioned that I had read on here once, way to possibly 'break' a broody (I've never done it myself) is to dip her backside into a pail of water to lower her body temp. They jumped all over me, saying it would cause shock and probably kill her. Boy, I washed two of my hens backsides this weekend to clean them up a bit, and they seemed greatful...they weren't the least bit shocked!...maybe a little miffed.