Yes, I've noticed the noise too. It happened after the PP,I face this problem because I'm using different computers at home and at work, in the office screen everything seems ok,but in my laptop I see the noise after uploading... :o(
About the colors of the plumage- all of these ducks are male, when they are mature the males' head becomes completely brown (or to say copperish-brown is better I guess). When they are young the males heads are a mixture of white and copperish-brown. So yes, you are right, it has to do with age, the first one from the back is older than the other two.
Tadorna ferruginea Trio (66)