Aggressive Female Border Collie (Puppy, under 9 months)
My family purchased Echo when she was 8 weeks old, and most of the time she is an absolute delight to be around. However, around 6 months of age, she started showing some worrying behaviours. The first instance was when we invited my mothers sister over for the weekend. Echo had been lying down when my aunt reached over to pet her, and without warning she snapped at her arm. She didn't break the skin, but she did nip her. This wasn't the first time she had met my aunt, and she hadn't ever behaved like that around her before. We began noticing from that point on that Echo had a tendency to stare very intently at any guests we would bring inside our home—especially women. A similar instance occurred with me, where Echo was lying down, and I began petting her. She seemed to be enjoying it, she even rolled over to show me her belly which I read as permission to pet. But when I reached toward her to pet her again, she snapped at my wrist and gave me a small nip. Apparently she has since snapped at my father and my sister. Most of the time, she acts very playful and friendly toward us, so we've all been very confused by her actions. In the past few months since then, she has been very good to everybody in my family, but she's still very wary of strangers, especially when they're inside our house.
Aside from aggression towards people, she has also demonstrated dog on dog aggression. As early as 3 months old. We introduced her to a boxer puppy that was around her age when she was 3 months old (we were really hoping they would hit it off together). And although the boxer was submissive, and seemingly only wanted to play with Echo, Echo kept charging at her and snapping. We separated them and assumed that they just weren't a good match. We introduced Echo instead to our neighbours 3 year old dog and they got along very well. We assumed that bit of aggressive behaviour with the puppy was a one off. Unfortunately we were incorrect, she has (not every time, but more often than not) snapped at and initiated an aggressive confrontation with dogs she has met while on lead. More recently, while playing ball off leash, she ran at an elderly couple who were walking their miniature schnauzers. She sniffed noses with one, and then picked it up and actually shook it back and forth. If it had been a smaller dog she could have seriously injured it. We are at a complete loss as to what to do. Obviously we have resolved ourselves to always keeping her on a lead so as to prevent such a thing from happening again (which makes it difficult to exercise her).
I wish she at least gave us warning? She doesn't growl, she doesn't bare her teeth, her behaviour feels sporadic or random. Suggestions are desperately needed.