Im a little puzzled by this response. I dont wish to heap any blame on anyone, especially under such sad circumstances, however, we are all responsible for keeping all of our animals safe.
Given this dog was able to get at this bird while in the confines of his own yard, the blame can only go one way. The neighbour is not at fault, their dog was secured on their own property and they have a right to let him roam as well as we do to let our birds free range.
now, I am very sorry to hear of the loss of this bird, but try to learn from this horrible experience. Either confine the birds, adjust the fence to prevent them getting up on top, or clip wings. And as iwiw60 has said, ensure the fence is extra secure, it is likley the dog will now try enter your property.
Should this have happened