I actually had posted this in your breed and gender thread, but I see you've started a thread for this, so I will copy my reply here:
They look very undersized for their age. Even if you got them when they were day olds, they would be a month now, and they should be much much larger. My three week old Call ducklings are larger than your guys are, and Calls are a tiny bantam breed. Horus also looks hunched and not so great in the picture you posted.
May I ask what you have been feeding? And what you're doing for a brooder? Such as what kind of bedding are you using, are you using a heat lamp to keep them warm, etc? They really need a heat source of some kind, be that a heat lamp, a heating pad, a hot water bottle that you change regularly, etc.