Last night I was hanging out with my two pullets, Peep and Nibbles. Peep was being a good girl and sitting on my lap, letting me pet her. Nibbles however always feels a need to sit on my shoulder (or worse, sometimes my head). Last night she was on my shoulder and kept putting her head/beak in my neck, hair, and shirt and shaking it back and forth really fast. It didn't hurt, and she wasn't pecking, but I didn't like this behavior. It kind of freaked me out. Was she trying to preen me, or do you know what she was doing, or why she would do it? Can I stop this behavior?