I know the one is a mallard but im unsure of what the black and the grey ones are?
Edited by jenniferlamar70 - 4/28/16 at 8:58pm
The best way to tell is through development, seeing as the "mallard" is as big as the other ducklings(and if it is the same age) it is most likely a rouen. This is a prime example of how the eye stripe test is not 100% accurate. There still is a chance that it could be a mallard and is just maturing very quickly, but just watch it and if it is still just as big as the other ducks by 5 weeks it is most likely a rouen.