Sen. Chuck Grassley unwittingly sent a crude message to his constituents Saturday when a social media post went awry. Grassley (R-IA) smiled for the camera as he posed next to a sheep at the Iowa State Fair — apparently unaware of the photobomb behind him"My compliments to the sheep barn at the Iowa state fair for having warm water when u wash ur hands," wrote Grassley. "Pretty nice."Behind him, a young man's t-shirt delivered a contrasting mess…