I have two snippets here from stoot and Kukubee. stoot said that they used to play ball with players a long time ago, but the code's been busted since them. Kukubee said that they were used for testing flying animals. Looking at their behavior, I think they have the same behavior as chickens.
Lei, Jade and Little Poundcake have kittehs on their home streets, but they are devs. Unless you are talking about a player who has them...? *gets catnip out*