What killed my bunny ? (Graphic content warning)

We have Chickens and live on a hill with BLM land on 3 sides.
We got a Rhodesian Ridgeback from the shelter (HEMI)
a dozen years ago. We have not seen any Coyotes around here
much since then. These dogs were breed to hunt lions and a Coyote
is easy pickings for them. Very gentle and loving around the two-year-old twins
as well!
Ok I'll bite....what is BLM land ? And on 3 sides, so it surrounds you. Hope it's friendly.