I have 2 chihuahuas, Daisy and Delilah. We got Daisy as a puppy. She was 8 weeks old and pretty mature so it worked out ok. Her other three siblings were not even close to the level she was at and had to stay with their Mom longer than Daisy did. She was a gift from a friend so we knew about her habits and disposition already. Daisy had a mind of her own very early in life. I think 6 weeks old is definitely too young for your pup to be seperated from her Mom. Give it at least 2 more weeks. The longer the better in my opinion. Chihuahuas are very very small little doggies anyway, and as puppies, they're tiny and easy to step on. The more she can grow the better off you are. With your Boxer; we are just very careful to give both girls equal attention so neither feels left out. Giving all three of them equal time should take care of that problem. It sounds like you're sure going to have your hands full for awhile with a new puppy, a Boxer puppy, and another chihuahua. Chihuahuas do require alot of human attention and contact. Good luck with all three pups and enjoy them!!

Terry