Re: shadow
Try keeping him leashed in the house for a while. Just let the leash drag behind him, so when he starts to focus in on the shadows, you can grab the leash and correct the behavior. I would also try teaching him a "leave it" command as well. Use the command and when he doesnt respond, correct with the leash. GSD's are very intelligent and he should pick up on the "leave it" command pretty fast. It will also help later on if he starts to get into anything else, *leave it* will be a great help!
Try keeping him leashed in the house for a while. Just let the leash drag behind him, so when he starts to focus in on the shadows, you can grab the leash and correct the behavior. I would also try teaching him a "leave it" command as well. Use the command and when he doesnt respond, correct with the leash. GSD's are very intelligent and he should pick up on the "leave it" command pretty fast. It will also help later on if he starts to get into anything else, *leave it* will be a great help!