What a super long thread!
First things first - Julie87 ... if you are using a shock collar / e-collar on your puppy to stop it from biting your siblings you are doing it WRONG. I have respect for a number of training tools, and I do respect the e-collar as a tool, to be used APPROPRIATELY. Shocking your dog because it behaves inappropriately around your siblings is WRONG ... there are no if, ands or buts. YOU should have trained the dog to act more appropriately, and if you haven't yet, then keep the dog on leash, or in its crate.
Bubbles - you have received a ton of information here, and a lot of it is confusing, contradictory and likely doesn't make sense. Everyone is offering their personal experiences of what worked for them with their dogs / or dogs in rescue / foster, whatever.
You feel that the problems with you and your dog are unique. You're right - they are unique ... no one else has the same problem as you ... do you know why? Because they are not YOU.
Your puppy is really no different than any other GSD landshark out there. It might be a tad more hyper than someone else's puppy, but seriously, all puppies go through the teething stage, and there are always some puppies that are just "more" than some others.
So, yes, your situation is UNIQUE, because the only thing different is YOU.
Bubbles, you need to step back and realize that you are the problem with your dog. You are not consistent, training is only done in "blocks" of time, you are rewarding when you should be redirecting, etc.
I'm not trying to "slam" you or push you into a corner to get all defensive. Most of us have probably been where you are now, with our first dogs. Looking down at this monster and trying to figure out what the heck we did wrong.
The reality is, bad behaviour in dogs is a result of incorrect training, or no training.
My suggestion ... which has been said in here before - credit to whoever posted it first!
1 - pick ONE training method and stick with it ... quit confusing your dog! You have so many "punishments" for your dog when he bites the dog hasn't a clue what's coming. Dogs need to know that if I do "A" then "B" will happen - your puppy is confused
2 - quit going to the vet for behaviour / training - most vets know nothing about training, you're wasting your money going back there
3 - CALM DOWN - you feed the energy to your puppy with all your frustration, anger, resentment, etc. And, please, don't try and tell me / us that you are calm when you are working with your dog and when he bites you. I won't buy it. I've been there, and so has everyone else ... any inexperienced dog owner, or even novice dog owner, is going to react when their dog / puppy bites / nips them. It's human nature ... just that simple reaction causes your dog's energy to escalate ... and then there's a war ... who's gonna win? Won't be you!
4 - Training is NOT done in 20 minute blocks here, 10 minute blocks there, etc. Training a puppy is 24/7 ... or at least as long as the puppy is awake. I had Kyleigh attached to my waist for the first 4 months while we were in the house - unless she was sleeping or we were playing outside. This taught her to follow me, respect my space, and I was able to watch her and make sure she didn't get into anything.
You mentioned that your puppy eats everything off the ground ... tighten the leash a bit ... and walk faster. I didn't give Kyleigh free rein to sniff everything she wanted when we walked ... I'd have never made it around the block. At 5 months, I'd walk about half a block and then stop at a corner (making sure there's no garbage or anything) and let her sniff for a minute or two. Then we'd walk again. No stopping, and walk quickly. Don't give him a chance to stop and smell the roses. You'll give him that later.
Finally, you need to find a trainer you like and will work with YOU ... not your dog ... YOU. Most of us on here could take your dog for 2-3 weeks and have 90% of your dog's "problems" under control or even gone. But until you are trained in how to do it, your dog will revert back to being the way it is, because you don't have the tools to figure it out.
Bubbles, we can't "help" you on line ... No one is here to SEE you interact with your puppy. We can provide advice, information and suggestions, that's all.
I really hope you can find a good trainer - you've been given a list of people to contact (and seriously, why do you continue to spend money on a trainer that won't address your main issue?) and that in 3-4 months from now, you'll look back on the horrors of the landshark phase and laugh.
Marion’s Zoo-Kyleigh, Raylan-cat, Echo-TAG,