Change in Goldens Behavior

Question
I have a 14 month old female Golden.  She has been trained and has been great learning most things.  She quickly picked-up recently on my putting her in a sit-stay before she can eat.  I always did this, but very recently as soon as I put the bowl down she sits down immediately, looks up at me, and waits for my OK to eat.  "Come" has always been an issue - she'll only do it in the house.  

In the past 2 months however her behavior has changed to where she is more aggressive and rebellious.  She jumps and bites at us when she wants to play or go outside - 9 times out of 10 she does not have to go potty.  She'll just sit outside the door and look around or lie down with a nice juicy stick. She's started to dig.  Never a "chewer" of furniture or shoes, she has started to gnaw at our moldings in the doorways and the base of our kitchen cabinets.  She's never been allowed on furniture unless invited but now when we come home we'll find her on the sofa - in a room where she spends lots of time with us but has NEVER been allowed on the furniture.  Yesterday I found she had knocked an envelope off our coffee table and ripped it into a million pieces.  Is this just a phase?  Will she grow out of it?

Answer
She is maturing, and may be less satisfied to quietly stay home all day.  I never have such problems because my dogs are crated when we are gone.  The training she has had may have lacked the proper focus.  The key to most behavior problems is approaching things using the dog's natural instincts.  Dogs see all the people and dogs in the household as a pack with each having their own rank in the pack and a top dog.  Life is much easier if the 2 legged pack members outrank the 4 legged ones.  You can learn to play the role of top dog by reading some books or going to a good obedience class. A good obedience class or book is about you being top dog, not about rewarding standard commands with a treat. Start at http://www.dogsbestfriend.com/  For more on being top dog, see http://www.dogbreedinfo.com./topdogrules.htm

She may also need a richer life.  If you are leaving her more than 4-5 hours at a time, you need to find somebody, a neighbor or professional dog walker, to give her a mid daybreak.  Spend more time with her, even if it is playing fetch in the back yard.  Do you have dog parks?  One good solution is doggy daycare.