great dane and chewing

Question
I have had great danes in the past and many other breed, but i have never had a dog that i could not train to not chew. At the time of receiving the dane i did not believe she was the age the previous owners stated she was, and did not provide me with papers. We have dog-proofed the house as much as possible but she seems to find something new everyday-now it's soap and rubber ducky bathtub mats. Nothing stops her and she has two other dogs to play  with- but the Chihuahua-Beagle is not fond of her-and a large laundry basket full of toys.
I'm gone from home approximately 9 hrs./day M-F and my roommate is only gone 2 days/wk for 5  hrs and she still destroys the house in that time frame. She does not chew while we are home, and plays with all her toys. We have friends that come over, she visits them and has a backyard to play in.
I do feel she may have been mistreated from previous owners because she is extremely attention seeking as she follows me even to the bathroom. She will check on us when we're sleeping, and check constantly on my roommate when i leave the house for work. The good part is that she does not, what appeared, to have to fight for her food.
What else can i do and/or what am i doing wrong?? HELP!!

Answer
Unfortunately this may be a problem caused by bad training or no training as a part from her previous owners.

The only advise I can give you is to buy her a crate or exercise pen so that she is not getting into things and chewing on them while you or your room mate are not home. If she is used to being home alone for extended periods of time, the crate or exercise pen is your BEST option.

It is not cruel to crate your dog for an extended period of time, however I would also advise you to be more proactive with exercise, as chewing sometimes has to do with lack of it...

Just having a backyard and other dogs to play with does not constitute good enough exercise for this breed...being that you work 9 hours in the day, try to find the time to walk her twice a day for 30-40 minutes and this may suppress her need to chew on things in your home which can also be very dangerous and life threatening in some cases...

GOOD LUCK!!!!