It sounds like resource guarding and the resource is you. Dealing with it requires more expertise that I have, and more than a regular trainer will have. Some owners have had success using a certified behaviorist. Your vet may be able to help you locate one. A good one won't be cheap.

I'm a little surprised the GSD hasn't "corrected" the unruly youngster, but a serious correction could result in a major injury or worse.

 

Three days is a very short time, and you mention that the Golden seems anxious, so this could definitely be an expression of that anxiety. She is in a new environment, she doesn't understand the new rules or order of things, and she doesn't know if she will just be moved again at any moment. On top of that, there's already a resident dog. It does sound to me like a bit of resource guarding - with you being the resource. But considering how short a time she has been with you, I would suggest that you give it time and patience to see if things settle down.

There a kind of "rule of threes": 3 days to decompress, 3 weeks to learn the rules, and 3 months to feel at home. It's a bit too pat for my liking, because of course there is such variation in dogs and circumstances, but as a rough guideline it is helpful. Your new dog is only in the very first part of that. One of the rules she needs to learn is that she has to live with another dog....but also she needs to learn that living with the other dog doesn't mean she won't get all the attention and love that she needs.

You have a great advantage that your GSD is being neutral. It's also a good sign that even in three days you are seeing signs that perhaps the anxiety in the golden is easing a bit. I recommend keeping the dogs separate at all times for now, just because apparently being around the other dog is anxiety-producing for the Golden.

Take her for nice long walks, play with her if she is interested in play. Do lots of petting and talking to her and reassuring things. Just love on her a lot. As she starts to relax, maybe in another couple of weeks or so, you can think about reintroducing the dogs, on leash and in the back yard. Do this with two people: let one person handle the GSD on leash and the other the Golden, keeping them in sight of each other but a good distance apart. If the Golden seems the least bit anxious, increase the distance between them until she is calm. While the Golden is in sight of the other dog, give her lots of petting, treats, and praise, so that she starts to get the idea that being around the other dog doesn't mean she won't get what she needs. In fact, seeing the other dog means good things will happen for her! T his is the concept you want her to get.
And, of course, feed them entirely separately with closed doors in between (which you are no doubt already doing, but I suggest that you plan to do that indefinitely just to make sure that both dogs feel very secure about their meals).

Goldens are typically pretty mellow and friendly dogs. If this is new-home-anxiety, she will settle down within a month, maybe less. Just don't t ry to speed up the process, because one of the most important things with a new dog, especially a rescue, is to let them take the time they need to settle in and calm down, however long that is. I know keeping dogs apart is no fun, but I doubt that you will have to do it forever, especially if you take things slowly.
If the anxiety doesn't diminish in another month or more, there may be other issues with this dog, but give it some time. Best of luck!

 

Three days is a very short time, and you mention that the Golden seems anxious, so this could definitely be an expression of that anxiety. She is in a new environment, she doesn't understand the new rules or order of things, and she doesn't know if she will just be moved again at any moment. On top of that, there's already a resident dog. It does sound to me like a bit of resource guarding - with you being the resource. But considering how short a time she has been with you, I would suggest that you give it time and patience to see if things settle down.

There a kind of "rule of threes": 3 days to decompress, 3 weeks to learn the rules, and 3 months to feel at home. It's a bit too pat for my liking, because of course there is such variation in dogs and circumstances, but as a rough guideline it is helpful. Your new dog is only in the very first part of that. One of the rules she needs to learn is that she has to live with another dog....but also she needs to learn that living with the other dog doesn't mean she won't get all the attention and love that she needs.

You have a great advantage that your GSD is being neutral. It's also a good sign that even in three days you are seeing signs that perhaps the anxiety in the golden is easing a bit. I recommend keeping the dogs separate at all times for now, just because apparently being around the other dog is anxiety-producing for the Golden.

Take her for nice long walks, play with her if she is interested in play. Do lots of petting and talking to her and reassuring things. Just love on her a lot. As she starts to relax, maybe in another couple of weeks or so, you can think about reintroducing the dogs, on leash and in the back yard. Do this with two people: let one person handle the GSD on leash and the other the Golden, keeping them in sight of each other but a good distance apart. If the Golden seems the least bit anxious, increase the distance between them until she is calm. While the Golden is in sight of the other dog, give her lots of petting, treats, and praise, so that she starts to get the idea that being around the other dog doesn't mean she won't get what she needs. In fact, seeing the other dog means good things will happen for her! T his is the concept you want her to get.
And, of course, feed them entirely separately with closed doors in between (which you are no doubt already doing, but I suggest that you plan to do that indefinitely just to make sure that both dogs feel very secure about their meals).

Goldens are typically pretty mellow and friendly dogs. If this is new-home-anxiety, she will settle down within a month, maybe less. Just don't t ry to speed up the process, because one of the most important things with a new dog, especially a rescue, is to let them take the time they need to settle in and calm down, however long that is. I know keeping dogs apart is no fun, but I doubt that you will have to do it forever, especially if you take things slowly.
If the anxiety doesn't diminish in another month or more, there may be other issues with this dog, but give it some time. Best of luck!

First off, thank you for the long and well-thought out reply. I really appreciate it.
I’m trying to do these things with the golden, but I’m worried about having to neglect the GSD in the process. Currently she’s stuck outside in her run for most of the day (I take her out for bathroom breaks and for exercise, but I can’t be with her all the time and still deal with the golden). She is used to being an inside dog, and it is also starting to get colder outside. I’m worried that if the golden can’t learn to accept the GSD being in the same space as her and receiving attention from me in the next 1 to 2 weeks, it’s going to start having repercussions on my GSD. I do have baby gates installed throughout the house (the GSD is very reactive towards strange humans, so we like to have an airlock system to make sure everyone is safe) but I’m worried about fence fighting/aggression from both of them.

 

Can you close doors instead of using the baby gates, just for now, to avoid the "fence fighting" possibility?
And, I fully appreciate your concerns about the GSD...I would have the same ones in your place. But I think that if you can divide your time as equally as possible between them, giving them each a lot of positive attention, your GSD won't necessarily suffer as a result. I wouldn't suggest leaving her outside, but rather having both inside but in separate rooms with doors closed, preferably as far apart rooms as possible.

Does the GSD sleep in your room? If not, maybe you can allow that for now, so that will be time spent with you so that dog doesn't feel neglected. Any thing that you can do that would be extra nice for her would help her not to feel usurped.....which is very important in this situation.

I realize it's a tall order, giving extra special attention to them both, and probably you have work to do and it all somehow has to fit into 24 hours! But, keep in mind that this situation is temporary. And if you were to let the GSD sleep with you that would be all those hours she gets to have you to herself. I think that would help.

Taking it one day at a time and celebrating small wins as the Golden becomes more relaxed will help all three of you, I think. Try not to think in terms of how fast this all has to come together, and instead focus on the positive changes that you see day by day. In this kind of situation, I sort of have a "don't look up" approach to things.....meaning not looking too far ahead or worrying about what-if. I just focus on today, do my best to encourage and support the dogs while keeping everyone safe, and see if tomorrow will take care of itself if I am patient.

 

Can you close doors instead of using the baby gates, just for now, to avoid the "fence fighting" possibility?
And, I fully appreciate your concerns about the GSD...I would have the same ones in your place. But I think that if you can divide your time as equally as possible between them, giving them each a lot of positive attention, your GSD won't necessarily suffer as a result. I wouldn't suggest leaving her outside, but rather having both inside but in separate rooms with doors closed, preferably as far apart rooms as possible.

Does the GSD sleep in your room? If not, maybe you can allow that for now, so that will be time spent with you so that dog doesn't feel neglected. Any thing that you can do that would be extra nice for her would help her not to feel usurped.....which is very important in this situation.

I realize it's a tall order, giving extra special attention to them both, and probably you have work to do and it all somehow has to fit into 24 hours! But, keep in mind that this situation is temporary. And if you were to let the GSD sleep with you that would be all those hours she gets to have you to herself. I think that would help.

Taking it one day at a time and celebrating small wins as the Golden becomes more relaxed will help all three of you, I think. Try not to think in terms of how fast this all has to come together, and instead focus on the positive changes that you see day by day. In this kind of situation, I sort of have a "don't look up" approach to things.....meaning not looking too far ahead or worrying about what-if. I just focus on today, do my best to encourage and support the dogs while keeping everyone safe, and see if tomorrow will take care of itself if I am patient.

The GSD does sleep in the room with me. Behind doors isn’t really going to work, as the house is what one might consider “an open concept”. Outside is the only option for me to keep them separate at the moment, otherwise I would definetly have the GSD inside.

I really appreciate the encouragement. I’m trying to keep in mind that it’s only been three days, and I’m hoping the golden will mellow as she adjusts and become more receptive to the GSD.

 

I agree with RonE. I would consult with a certified behaviorist, one who is experienced in dealing with resource guarding issues. In your shoes I would also be open to rehoming the Golden. My reasoning is that I haven't truly rescued an animal if bringing that animal into my household causes stress to both the new and the existing animals. It sounds like you have a lovely patient German Shepherd. She doesn't deserve to have to deal with a maladjusted snappish teenaged puppy. As RonE also mentioned, you don't really want things escalating to where the Shepherd feels her only remaining choice is to solve the situation with her teeth.

 

I agree with @Curls & @JRonE you need to get a qualified trainer/behaviorist involved sooner rather than later. Golden's are typically very mellow, but at eight months of age and probably little if any socialization all bets are off.

 

@Curls and @JRonE are probably right. I always want to support the idea of giving things time and patience to see if they will settle down, and I still think in your place I would give it a little bit more time and close observation to see if the Golden calms down.

But it is true that it's not fair to your GSD, and it shouldn't go on long enough for the GSD to have to defend herself. It's also true that two female dogs are harder to integrate into a happy pair than a male and a female. If things don't get better fairly soon, and you really want to keep the golden, a consultation with a behaviorist would be a very good idea. Someone who is there with you and who is fully qualified will be better able to determine if the Golden just needs more time and some gentle training or if you should consider rehoming her.

Just make certain in hiring someone that they use exclusively positive reinforcement training methods. Ask them about their methods before they come to your house. Any mention of using a choke collar, e-collar (even if "only on vibrate"), loud noises or a shake can, a slip lead, or any other form of aversive training will only make the situation worse and could do permanent damage to both dogs.
Wishing you the best of luck.

 

This reminds me of my lil’ guys relationship with my best friend’s dog! Sadly, my friend’s dog has since passed.