GSD Defense Drive ? Help!

Question
I am the proud owner of an 8.5 month old GSD. Achilles is a healthy 86 lb. West German working lines sable. We live out in the country on a lot of land where he can run free. He shows tremendous prey drive, chasing everything from squirrels, lizards, birds, bugs, and coyotes off of the property.  At the same time, he is very gentle, and sociable with other dogs in the neighborhood.  The problem, is that Achilles does not seem to defend himself when he ends up in a situation where he needs to.  The first time, a neighborhood dog had attacked him and Achilles just rolled on his back and yelped until I could get there.  One of the other dogs is a 12 lb. rat dog that is a bit too overbearing at times, and Achilles seems a little intimidated by this as well.  Most recently, 2 nights ago, he starting barking and growling something fierce; I ran outside, and he was already around 200 yds away behind a neghbors house having chased "something" form the yard (around here it could be a racoon, coyote, bobcat, another dog, boar, etc.). I heard him yelping in the distance and fired my shotgun in the air, wnding whatever was going on. Achilles came back with a 2 inch gash on his right thigh down to the muscle; fortunately, our vet met us at the clinic even at 9:00p.m. to sew him up.  My concern is that Achilles herding and protection instincts are putting him in situations where his defense drive is failing him.  Regardless of how uncomfortable he is, he continues to confront these "threats", but continues to fail to protect himself. We are worried about him. Please help us understand what is going on, and what we can do to helpl him. Thank you, Carlin.

Answer
This isn't an area I have that much experience in.  I am not a big fan of letting a dog run loose.  Perhaps think of fencing a large area of yard, and let him sleep inside.  And make it a 6' high fence, otherwise he may sail right over it.  If you see any problems with him sleeping inn the house post back and i will help with them.

Dogs do become more protective as they mature.  It is a common problem for them to become too protective by the time they are 3.  so you can hope he improves.  

If you are still feeding him puppy chow, you should change over to adult.  It slows growth and gives sturdy joints more time to develop.