Chicken Runs
My intro to night cargo was flying a Beech 18 with around 10,000 passengers from Ankeny Iowa to Opalocka (recently hatched baby chicks for export to Columbia).
They didn't smell yet (they were to young to even sh#t yet) but at the end of the flight your throat would be sore and dry and everything in the airplane was coated in yellow dust (from calcium that coats their feathers as they grow). We also flew altitudes based on temperature instead of winds to keep them happy. Try explaining that to ATC. It was a little different.
You don't hear much of their complaints once you crank up those two P&Ws but an old hand told me that "They peep when they're hungry. They peep when they're too hot. They peep when they're too cold. If they're quiet, it means they're either happy or dead."