So I have cornish crosses. I don't ever see them preening really, they all have a lot of pin feathers yet and are just kind of dirty looking. They're pretty friendly, though, and I started petting one with my fingers like a comb, on the back near the tail. She started making little snapping noises with her beak and immediately started preening. It worked on all of them, even the roosters. They even started grooming the bird next to them if they were sitting next to each other. Pretty funny stuff - I tried it on the little egg layers and it didn't work!
