We're in a drought but back in spring when we had rain I never once seen one of the chickens looking up. They did like to run around in it though, or they were just to dumb to find shelter from it lol.
I've seen chickens looking up, but not in the rain. After my first hen was carried off by a hawk the rest of the flock refused to come out of the coop for a solid 7 days. When they finally ventured out, they would all stand in the doorway and look up and stare at the sky, then they would RUN as fast as they could to the trees across the yard. They did this every time they needed to cross the open part of the yard and it continued for at least two weeks.
It was a little funny when they were in the coop. I would open the door and they would all just stand there and look at me. I would walk up real slow and hear them inside, talking to each other, then I would open the door and they would just STOP and stare at me. I would close the door and they would go back to talking to each other. I half expected them to be building a anti-hawk weapon in there.