The dog park & other areas are "neutral" territory. She may be defensive at home because it's her space being invaded. My schnauzers bark like crazy when they see the neighbor walking his Dobermans on a leash down our road. Once he's out of their sight they're fine. I think they feel like they are "on guard" for any danger. Since Selena was attacked on her "home territory" she may now be hyper-vigilant about protecting it from any perceived threat.
It has been my experience with fear aggressive dogs that rewarding them by treats or reassurance isn't always good. It tends to make them think they're doing the right thing by being this way. Distracting them with the shaker bottle is a good idea & then treat them once they've turned their attention to you. Eventually she'll learn that when the shaker rattles she gets a treat & it'll be easier to ignore what was setting her off. It'll take work but patience is key.
Stay with her when the trigger situation happens & distract her while keeping her in the same area. For example, if she lunges at the window then stand by there with her & shake the shaker bottle without moving her. Make her turn from the situation. Once she's distracted, talk & pet her then give a treat. Just say something like "who wants a treat?" or something like that. If you see the child or dog has gone from sight then let her see that "threat" is gone. Keep doing that until she comes to understand it's ok when these things come into her space.
Having a familiar dog come over could be a very good thing. If you can get the trainer to come to the source of the problem it's a lot easier to find a solution. I remember having a friend who would say their child would never go to bed without a fuss. When she spent the night at my house I never had a problem. That's because she was in a different situation. Might be the same with your sheltie.
Good luck.
It has been my experience with fear aggressive dogs that rewarding them by treats or reassurance isn't always good. It tends to make them think they're doing the right thing by being this way. Distracting them with the shaker bottle is a good idea & then treat them once they've turned their attention to you. Eventually she'll learn that when the shaker rattles she gets a treat & it'll be easier to ignore what was setting her off. It'll take work but patience is key.
Stay with her when the trigger situation happens & distract her while keeping her in the same area. For example, if she lunges at the window then stand by there with her & shake the shaker bottle without moving her. Make her turn from the situation. Once she's distracted, talk & pet her then give a treat. Just say something like "who wants a treat?" or something like that. If you see the child or dog has gone from sight then let her see that "threat" is gone. Keep doing that until she comes to understand it's ok when these things come into her space.
Having a familiar dog come over could be a very good thing. If you can get the trainer to come to the source of the problem it's a lot easier to find a solution. I remember having a friend who would say their child would never go to bed without a fuss. When she spent the night at my house I never had a problem. That's because she was in a different situation. Might be the same with your sheltie.
Good luck.