Ravens and a murderer GSD... (Semi-Graphic Description)

Hello! I am looking for advice on two issues... the first, and most important, is that for the either third or fourth time, my seven and a half month old German Shepherd puppy has killed/maimed one of my birds. The first time it was a Buff Orp hen that she tore apart (literally, the chickens lungs had been removed from its body) and in the same day--- although she was never found--- a Black Giant hen disappeared into thin air. This was around October-November, not exactly sure. We have speculated that the cause of this behaviour was a bear attack a few weeks earlier, taking just under 3/4 of our 14 birds in two seperate days. We figured that all the blood, fear scent, etc. that was in and around the coop and run could have triggered it.
Meanwhile, two or three weeks later, my mother looked out the window to see her relentlessly attacking our Pekin drake. He survived, but his air sac was puctured and it cost us $80 in vet bills to stitch him up.
And now, after a month of vacation in Hawaii, we come home to find that our petsitter, not wanting to ruin our trip, had kept to himself that she had killed my last guinea fowl THREE WEEKS AGO! According to him, she brought him her head and he later found a pile of her feathers near our hen coop. He says that while two of our dogs where accounted for, our third dog and his pitbull most likely participated in the kill, because there was nothing beside the head left and there was no way she ate my guinea all by herself! So now, this mutt has dragged our other dogs into the mess too, in addition to all the bird losses she's caused!

And despite all this, my parents downright REFUSE to rehome her, despite the fact that we have lost two good laying hens and a dear pet to her!
So... I need help! I have heard that some people say, "once a dog gets a taste for livestock blood it'll want more" and blah blah blah... I know this is not true in some cases because I have a setter mix that killed our Rock pullet five years ago and hasn't touched a bird since, and I trust her completely around my birds--- but she did nothing more than break that hen's neck... this GSD has TORN APART three birds, or at least two, since we don't know what happened to the Giant... although one can only assume...
Is there anyone here who knows what type of training she needs? Any suggestions? I am trying my best to keep all five of my remaining hens inside the pen but I am sure one of them will get out someday, and in the meantime I have an order of nineteen day old chicks on the way, due Apr. 1st!!!!!!


The second issue is far more minor, but still aggravating. For months now, every time I go up to our chicken coop in the morning, always before 10:00 AM, there are anywhere from 2-5 ravens in the pen! They are stealing my chicken food and scaring the chickens; when the ravens are in there they hide, looking absolutely terrified, in the corner! And I've been worried about the ravens spreading disease/mites/whatever among my flock. I have gone on several chases through the forest with my BB gun, but every time the ravens see me coming they recognize the gun (and me) and fly away as fast as possible... I still haven't had any luck hitting them... yet...
We plan on covering over the roof of our pen with chicken wire, it's already partially done... but in the meantime is there anything I can do? These birds are driving me CRAZY!

 

OK, thank you! I didn't even think about the fact that the ravens could be taking our eggs, but the only chickens we have are four pullets who should have been laying by now, but haven't. The only eggs we seem to get these days are the three or four per week our 5 year-old Plymouth Rock has been laying, I guess the ravens haven't got to those... Ugh, I should have guessed that they were stealing them, my mom works with a wildlife rescue organization and she and I have been to a few classes about them...

I'll have to get the wire up ASAP. I would have already, but it's a two person job because I have a strand of hotwire running around the fence right where my elbows would be... I stumbled into it once and would not do it again, it has the strength to keep a bear out...




As for the dog... I have been trying to train her not to look at them or pay any attention to them... it is sort of working... whenever I let out the chickens and care for them in the morning I bring her with me on a leash, and have her lay next to the fence inside the run... It's so hard to make her stay there though, not because she tries to leave but because GSDs are incredibly expressive dogs... she gets this super-depressed look on her face; however, on the good side, yesterday one of my Americana pullets walked right up to her, only a few inches away... she didn't move a muscle. She knew it was there, I could tell because she was looking at me like I was going to get mad at her, but she just looked straight forward, didn't even tilt her ears to listen to it or lift her head off the ground. I'm just keeping my fingers crossed that I can get her to stop killing them.
And as for obedience training... that will be interesting. Our other three dogs besides the GSD understand the commands "Sit" and "Catch the treat!" and that's about it... I was fairly young when they were born/bought (one of them is the other two's mom) so I didn't help with the training and my mom had so much on her plate she never got around to it... so seven years later, they are all still untrained and unruly, and the pup has practically been taking lessons from them...

 

OK... thank you all for your advice on the dog!
And the ravens are finally gone! I covered the run with chicken wire/black plastic bird netting. It works very well.

 

Well... I have predator proofed my run (I call it Fort Knox- it's 6 ft. chain link all around with cement at the base.) Problem is, I like to free-range my hens but I always have to be up there watching them when I do, and I do not have much time to spare to do that with them... so I can't really free-range them as much as I want to.
And my mom refuses to kennel her, or put her on a run. although she has been acting better around the hens lately... the other day one of my Americaunas flew up into the air in one of her "crazy fits" when Thora was walking by and she didn't do a thing.