It may bit a bit difficult, but you might be able to work with them even if they seem aggressive. I started out with 3 trios of very obnoxious adults. I handled all the resulting litters daily, fed off the obnoxious parents as soon as possible and only let the friendliest ones reproduce. I now don't have any I would consider aggressive. They range from totally ignoring me when I pick them up to licking my fingers and crawling around on my shoulders if I allow it.