Okay, so for now they have been called the "nice one" and the "timid one". The nice one has a white chest and more white altogerher, has a friendlier demeanor, hisses more, is slightly larger, and seems to be the leader of the two. The timid one is shy and easily scared, has dark brown feathers on her front and more in general, makes almost no noise despite the occasional hiss,is slightly smaller. They both hiss, they both have that thing where the top of their head fluffs up, they both started growing feathers at the same time. We got them when they still had down and within a month they have grown feathers and just bigger in general. I've never had ducks before, always been a chicken lover, so I'm 100% clueless. I'll try to post pictures in the comments below.