I have one male muscovy, about four months old and two female, same age. They are pretty social and friendly with me. They never bite or attack. However, recently, if I am sitting or squatting in the yard, my drake will run full speed and chest bump me, usually to my back. He doesn't scratch, hiss or bite. He just chest bumps me and then stands there and tilts his head at me. I am not sure if he is being aggressive, playful or amorous. He is not hurting me but if this is the beginning of aggression, I don't want to let it go. Usually I just take a flat palm and gently bump him back. Should I take this more seriously?