In the pics they are the two with the darker heads and darker markings on their backs. I tried to get pics of them preening but if course as soon as they see me, back in the water they go! The two with the darker heads also have much darker chests as well.
Does any of this really mean anything at this age? I do know that as three day old ducklings I remember their beaks being significantly darker as well. I don't have pics from then because they were originally two of my sister's three. We ordered six, three for each of us, but she developed buyer's remorse, so I took hers.
Thanks in advance for any and all input!