I have a lot of mixed-breed bantam hens and many of them will go broody. Some go much more frequently than others, it must all depend on the little voices only they can hear in their heads. I too had a chicken hen who incubated & hatched duck eggs. It was a little bantam and it wasn't long before her duck children towered over her. But they wouldn't listen to her when she called them over as she scratched, and she wouldn't listen when they begged her to take them swimming.