Different size d. auratus

[marilu]

Is it unusual to have young adult frogs that stay on the smallish side while others grow like hogs? I got three d. auratus in March, all the same size...young adults. Now one has grown a little, though it's still small. Another is REALLY big, almost doubled in size since I got them, and the third is somewhere in between. All three seem very healthy and eat well.
Is the really large size normal? There doesn't seem to be any dominance issues, though the smaller one is somewhat shy. Is there a difference according to gender? Just wondering about all this.

Thanks for your help!