What were you feeding them?
Iams and Eukanuba.
Now that I think about, I believe our vet was suspicious of certain foods even then. Living where we do, we have few neighbors, but those we do have reported similar problems. Our nearest neighbor lost her Yorkie to a mountain lion last month and her kitty to renal failure. Our other neighbor to the west lost a yearling colt to a mountain lion a couple of weeks ago. Actually, we are more worried about the increasing lion problem.