Right now I would absolutely have to say, DUCKS! I just hatched 18 ducklings who are housed with 23 chicks who hatched on the same day. Guess who comes running to me when I open the brooder door. I open the door and start talking to the babies and all the ducks run to me talking like crazy. It's the funniest thing ever.
Although I do love the fact that my chickens earn their keep. I sell their eggs and hatch them.