I have some interesting observations about duck behaviour to share.
I had a male called Peking. While’st very friendly, he was also very moody.
If I upset him in anyway he would take a bite out of my arm or leg.
In a good mood he would nibble me all over, but other times he would
bite and if I smacked him he would become enraged and attack me. I had to get rid of him
because I was never sure what mood he was in.

I kept two of his offspring, two females. Naturally one dominated the other
who was pretty shy, staying in the background while the other was very tame.
Lets call the friendly, dominant one No.1, the other No.2.
After a year no.1 started fighting with no.2. I separated no.1 from no.2. No.1 did not
like this - no.2 did. The result of this was that their character rolls were reversed.
Now no.2 was the friendly duck while no.1 would not let me touch it.
Previously I had to cut their wings because they kept on flying over the fence
into the road. Well no.1's wings were growing back. It kept on flying over the wall
into my swimming pool. I cut it’s wings once more. This resulted in an immediate
transformation. It has been very tame since I cut it’s wings. They now both are
friendly, don’t fight, play with my dogs, and regularly go for a quick dip in the pool.
I hope this lasts.