The biologist first took a look at the chicken, then proceeded to prod and poke it, however, could not offer a proper diagnosis.
The chemist then took samples of the chicken's feathers, spit, etcetc, and proceeded to conduct chemical tests, however, also could not provide a proper diagnosis when he was done.
Meanwhile, the physicist was furiously working through some monstrous calculation when finally, he raises his head and says,"I KNOW HOW TO CURE HIM!!!!! But it only works for spherical chickens travelling in a vaccum...."

Poor chicken....