Working at the pet-store, I've noticed that some hedgehogs come in quite the drastically different sizes. I thought our male was about as big as he got, don't have the exact weight however, but then I saw Bud

, this massive Hedgehog that was maybe 3-4 years old, quills were atleast ½-1 inch longer then ours, and he was maybe 2x-3x the size of our male. I thought maybe he was just that big due to his age, but he managed to impregnate Big Momma, and she was a nice average size at maybe 2-3 years. The babies she had we're massive as well, at 4 months they we're bigger then their mother already ... so to answer your question (sorry for long story

) I think it is genetic for size, as for weight, I would think it we're possible, judging by todays youth, or that they would be more susceptible to weight gain atleast.