I am a new owner of a beautiful 6 week old baby girl Rottweiler and I know very little about these animals. I have heard alot about the aggression and other things, but my sister-in-law has a1 1/2 yr old male and he is the biggest baby. Don't get me wrong he would protect when needed but never offers to bite my 3 year old son or our new pup. My question is are they hard to train? How long does the chewing last, if any? Are the females harder to have than the males?