Hard to tell from photos...are they the same size? Are their feet the same size? I am currently raising a large batch of 2-month-old muscovies (mine hatched July 2nd), and differentiating the males and females is super easy and obvious--the males are easily twice the size of the females. So if you have two of the same size, then I'd say they are most likely either both males or both females.
The green sheen on the black wings at first made me think male, but I have a female magpie with a green sheen on the black part of her wings, so I don't think green feathers always means male.
Also...you said they both still chirp? My males don't seem to make any noise except hissing. They used to peep, but they haven't done that in a while.
Hold on. Let me go look at my females and males and then come back to look at your photos lol.
Okay...yours look more feminine than my drakes. Also, my little wild type females (all chocolates and chocolate pied) are still smaller than my house cats, lol. How big are yours? I know it's relative, of course, but I wonder if yours are massive like my drakes. I swear, they are goose sized!
