Ducks with a difference in their feathers!

I found these 'manky mallards' again this morning, here they are shown above. I came across this group of Mallards in a pond on Monday. But were they all Mallards? I wondered , for as you can see from the following photos,one Mallard looks a bit different! There was a little hut at the edge of the pond which set me to wondering if they were domisticated? I find wild ducks in this pond each year but someone had built a cabin nearby in the past year. Is this strange duck maybe a manky duck? "Manky" is a term I came across this morning while doing a search for "domesticated Mallard" . The explaination of this term can be found at: http://10000birds.com/manky-mallards-domestic-feral-or-just-plain-odd-mallards.htm It seems to fit. I returned to this location yesterday but there were no ducks to be seen although I could see that the location of the little duck house had been moved. I will go back out there this morning to see what I can find there. note: I found these ducks this morning again and took the photo that is the first one on this page.Hopefully I notice that there are two manky males.!

In the above photo there are many similarities between both of these ducks, At first glance I would call them both male Mallards Notice that they both appear to have a mottled breast, but there is a noticeable difference in their bill colour

A Black Duck?

Not totally I see!

You have a white feather showing on your side,

where its not supposed to be!