Canine Digging

Question
I have a 12 year old female yellow lab. She grew very close to my husband during his battle with cancer, which he lost a year ago.  During my husband's illness, our dog began digging in the middle of our lawn.  It was a small area and I just repeatedly filled it back in.

After my husband's death in 2007, she began digging not just in her small area, but along our fence (sunny side)an in every place there is no plant.  Because I thought her digging was a result of my husband's passing, I've excused it, but she has dug holes the entire length of the fence!  

I've considered there may be rodents in my neighbor's yard, since she is not living there and a prior neighbor had the problem.  I had professional traps/bait delivered by a pest control company, but have not seen any evidence of rodents.

My question is...why is she digging and what can I do besides reprimanding when I catch her digging?  I appreciate any suggestions,
Kathy

Answer
Dogs dig because they're dogs, and there's little you can do with scolding - it simply doesn't work, and can make things much worse (well, if I can't dig here, maybe over by the petunias would work...).  If you can't beat 'em, join 'em.  Try making a sandbox for her (dogs love dirt that has already been dug, and the texture of sand is loose).  Now, the fun part.  While she isn't looking, bury some biscuits in the sand box.  Go get the dog and "help" dig them up together.  She will smell them under the sand (and we all know that Labs will eat anything LOL).  When she digs in the "right" spot, she gets an occasional biscuit (intermittent reinforcement), when she digs in a "wrong" spot, you simply redirect her to the right one and make it fun.  This method does require that the dog not be out alone for a very long time, but it's also the only thing I've seen that works fairly well to preserve your garden:-)