We had a dog that had a very good temperament, until shortly after new neighbors moved in next door. We lived in a mobile home park, (full of families and young children) at that time, so the next door neighbors were quite close to us. When we left our house to go out, we put our dog on a long leash outside in the side yard, next to these neighbors. We didn't have a fenced yard. In just a few months, our dog got more and more aggressive towards children. He never used to be like that as he was friendly towards children, as he was in a home with children. He was actually quite protective of children, especially my three children. But, more and more he would snap and bark at children. we were even afraid that he might bite a child. We could not figure out why.
That is, until another neighbor explains that she noticed that our next door neighbor's son, when we were away and also, when his parents were away, would come out and tease our dog. He would poke a stick at our dog and was mean to our dog. This boy was deaf and was over-protected by his mother. Even if we showed a video of her son teasing our dog, I don't think this mother would believe that her disabled son would do such a thing. So, we ended up giving away our dog to a man who lived out in the country. We knew then, that our dog really did need a bigger yard and would be happy going for long walks in the country, with this kind man.
It was a difficult choice to make but by the time we found out about our dog, there was not much we could do to change the situation. It was best to find a new and better home for our dog. That decision was best for our dog.
