What do i do with my german shepard?WHY IS SHE DOING THIS?

I currently have a German Shepherd girl who just turned one in late May. One thing German Shepherds love to do it chew. It's in their instinct. You must supply her with adequate chewing toys that are very tough. My German Shepherd must have chewed through twenty different toys. I found the best toys to be the Nylabone, but be sure to get the hard one and not the soft one. Another good toy is a hard plastic ball that lights up when it's chewed on.