I have a pair of Muscovy ducks - they are siblings and I got them as ducklings. I thought they were both females, but one has gotten considerably larger than the other and I am thinking that one is definitely a drake. I know their method of communication is mainly hissing, but I just read on this forum that the long drawn out hissing and stretching the neck down is a sign of aggression. I have not seen this behavior towards the other ducks in the pen - only towards me when I enter the run and walk around. He has not yet tried to attack, but are their any preventative measures I can take to dissuade him? TIA!