I think ducklings know who takes care of them. She may be sloshing - be careful how you pick her up. Are they getting a tiny bit of chick grit daily? They need that.
Drakes will overdo it with ducks. Sometimes to the point of injury or death. So we need to keep all flock members safe. This can be done by separating them.
Each flock is unique so you need to watch closely and consider splitting them up, rehoming at least one drake, or getting more females.
My best guess about duck-human relationships, given that they are all different because of the different individuals involved, is that ducks express affection pretty much one way . . .romantically. They play hop on top with each other, they flirt with each other - my all girl group. I think it...
My Runners did a little more flying - short distances, a couple feet off the ground - when they were that age. By the time they fully matured, they weren't even doing the wing-assisted jumping. They like to stand tall, flap their wings, and Vier likes to dance around and around while flapping...
Some folks keep drake flocks. Some keep the males and females separated. One person I know says she keeps the "Men's Clubhouse" at least a certain number of feet away from the females to reduce hormonal behavior.
Time was, I had the luxury of scanning the forums for quite a while. But now, sometimes I am so tired when I can get to the computer I fear I may miss something.
So, any eyes that can help me and get my attention are well appreciated!
Please, please tag me - my life is so blessed that I am often outdoors caring for ducks or plants or soil or other living things. Sometimes I even wash dishes and clothes .
But I check for notices several times most days. Never when I am driving.
I suspect that there is quite a bit of variation within a breed. For example, I occasionally read that some hatchery fowl don't have quite the laying capacity that the breed's reputation carries. I think there is some drift over time in a population.
I can see your concern, Rouens can get really chubby. However, this guy looks like he may be too slender. Can you adjust the food for now? You may be solving a problem that does not exist.
Ducks are unique - maybe he's not one of the overeaters.
Do you know how much food he's eating per day?