That's a good practical question. I have a friend, a long time wolfer and pro photographer who measured and photographed some skinned coyotes specifically to answer that question about 20 years ago. I just phoned him and was surprised at how small his measurements turned out, smaller than I remembered. He measured many, especially every time he killed a big one, and he never measured one more than 7 inches of kill zone, top to bottom at the deepest point in the chest. He was measuring from the top of the backbone to inside the sternum. He said that small coyotes would measure 4 inches or even a little less. Those are Interior of British Columbia coyotes. My personal impression is that they averaged a little bigger than coyotes in Southren California, couldn't compare them with anywhwere else.