Dog eating paper

About 3 months ago my dog started chewing up and eating paper, from the mail basket, recycle bin, wherever she can find it. She prefers mail over say, newprint or cardboard. She only does this when I'm away from home. I had chalked this up to separation anxiety, but this is a new habit that never occurred previously and nothing had changed in the home situation, food, etc., when this behavior started. The obvious solution is to always keep all paper in the house out of reach or confine her when we're not here, but I'd much prefer stopping the behavior. We have another dog as well who is also here when we are gone (we knows it's her from her poop). She does this whether I'm gone 1 hour or 8 hours Any ideas? She is a 7 yr old shepherd mix.
I don't have a definate answer for you, but I do have some ideas on the subject. My dog will eat paper too...she'll eat anything actually. I have been told by my vet that chewing is a serious behavior problem. My vet said my dog was chewing because she was bored and that I had created this type of behavior in her by giving her toys to chew on. She says that dogs need to learn how to entertain themselves w/o chewing. So, she suggested taking away all chew toys, putting the dog on a leash and then stepping on the leash so the dog just has to sit in one spot and learn to amuse herself that way. So, when you're watching tv, you restrain your dog in this way and the dog learns that it doesn't need to chew/eat things for fun. I'm not sure if this will help you with the paper problem and I don't have an answer for why your dogs chewing paper specifically, but the chewing/eating behavior can be put to a stop in the way I described. Hope this helps.
First, dogs are opportunitstic and chewing is a very natural dog behavior - they do it out of boredom, need, etc. I take issue with what the other responders vet said - this can actually frustrate a dog more because you are preventing a natural behavior as opposed to retraining. Again, dogs are opportunistic and even the best trained dog will act of the opportunity arises. Trust me, I am a trainer and behavioral consultant (and most vets get little to no behavioral training in college - my sister is a vet from one of the best schools and was shocked at the limit behavioral training given, also most vets are behind the times in current canine behavioral research and work with older and erroneous materials). Heck one of my dogs ate about a dozen cookies last night. They were cooling on the counter which is almost at nose level for her and it was just too much temptation when I walked out of the room and she walked in. My fault, temptation at nose level... She acted as any normal dog would have who could have reached the cookies... She ate half of them. Anyhow, when you are not home to monitor the behavior, you do need to remove temptation. I still put all trash in a closed bathroom when I leave and block off the nursery and family room. Since I am not home to monitor and make sure the dogs remember the rules of the house, it is not fair for me to leave them in a position where temptation can overrule training - and it will - dogs are animals, not little humans. So, continue to put away the trash whenever you leave. Now when you are home, if she begins to go for the trash, paper, whatever, stop her before she is actually in it. If you are too slow and she is committed to the act of paper chewing, you are no longer redirecting an undesired behavior but fighting against one in progress. Give a sharp "AHHH AHHH" to distract her and IMMEDIATELY give her a thing it it OK for her to chew. If you are not going to be in a room, then leash her and walk her with you so she cannto get to the room and eat the paper. But totally preventing her from chewing and doing a very natural activity is frustrating for dogs and frustration increases the likelihood of undesired behaviors. Prevention, removal of temptation and redirection is a better way of handling this.