Some Chi's are pretty small, only weigh 2 or 3 pounds, but I think the owner needs to take a bit of responsibility for this. I go out with my little dog to make sure no predators get her. Out here there are birds of prey, coyote, bobcat, mountain lion, raccoon. All of those could hurt or kill a small dog. I don't take the risk. She has a small enclosed (on all sides) yard she can go out doggie door to go to the bathroom. I reccomend that kind of set up to anyone with small dogs. It's just a dog kennel along the side of the house with a corrugated metal roof.
We have a black and white(mostly white) cat who likes to sleep on the nightstand at the bedroom window at night. We learned a long time ago to close the blinds because a couple of times great horned owls slammed into the window to try and get the cat. I guess they didn't see the glass. I don't know why the glass didn't shatter as it woke the DW and I(and the cat) out of a dead sleep. I went outside the first time and the owl got himself together after a few minutes and flew off. The second one wasn't so lucky. He was already dead when I got outside. It's truly amazing though how they can see the cat in the pitch black dark.
I watched an eagle try to swoop down on our pomeranian when we first moved here. If he hadn't ran under the patio table he would have been dinner. Ever since then I only take him out in our backyard on a leash. We have huge barn type owls here (no owl expert) as well.