Labrador Retrievers are intelligent and extremely active dogs. With these characteristics, leaving them alone will surely bore and cause them to think of doing other activities such as chewing, barking and digging.

This behavior can be very frustrating especially to dog owners who spend so much time and effort keeping the front lawn clean and beautiful.

If you want to know how to stop them,please check out the site
http://www.articlecity.com/articles/pets_and_animals/article_1514.shtml