I'm so very sorry for the loss of your little Chi. I can attest to that helpless feeling for sure. The DW and I lost a Boston Terrier puppy back a few years ago to a Possum. It is not something pretty too see to say the least. We rescued a full grown Boston that is blind in one eye 3 years ago and the first 2 years we live smack dab in the middle of 2 major highway construction projects that really drove the wildlife out in mass numbers. Our poor little guy got his share of attacks but thankfully he survived them all. We would always go out with him in the fenced in yard but the badgers weren't afraid of us or the dogs at all. They were so very quick that it was done before we could do much. This is in the middle of a large city none the less. You never know about wildlife or how quick it can happen.