Why did muskovy drake kick broody muskovy hen off nest?

[CaliFarmsAR]

My Indian Runner drake did that with my broody hen as well but left the eggs alone! I have two males and one is a great protector he would fight the drake that would take my hen off her nest!

 

[Quackwacker]

I think I figured out what actually happened. My mallard drake is attacking my muskovy drake and making the coup into a fight club. I removed the mallard and everything is quiet. My muskovy is pretty traumatized though. Poor guy. I don’t think he realizes he is 4 times the mallard size.