Adding another dog didn't work for my boy. Cause you are gonna split your attention for each dog. I have 11 month old male gsd and 6 months old female min-pin. I can see that my boy doesn't like him very much. After we got minpin, he got lots of diarrhea probably due to stress. I took him to the vet, he couldn't find anything, he said it might be due to presence of new dog. And another bad habit he got after I got minpin is him starting to eat poop. He never ever did that even when he was a puppy (he is still a puppy though). It sounds so nice to add another dog, but since he is a puppy, I wouldn't add another one till he is 1.5 yo at least. You know shepherds matures very slowly and accepted as a puppy till 1.5 yo. So basically it may work for you, but didn't work for me. And another thing is your pup is 6 months old. To raise a two pup at the same time is **** of a job. And you say he stays alone for 8 hours..German shepherds needs lots of attention especially during puppyhood. You have to be with them as much as you can. If Ii were you, I would wait till he is 1.5 yo at least. But again, this is just my opinion. If you have thatt much time and energy good luck. I hope it helps..