KYTrapper;
I have cleaned thousands of skulls including hundreds of coyotes and some domestic dogs (the dogs for osteological research purposes). I think I can speak with some authority that measuring the diameter of the skull will tell the average person nothing about whether the animal was coyote or dog or coy dog. Think about it. The physical features of some dog skulls is nearly identical to that of a coyote. Say, a collie for instance. A number of factors must be considered and measured when determining if a skull is dog, coyote, or coy dog.
Yes, although it is not real common, there are coy dogs. Don't let anyone tell you differently. I caught a female in late Jan. that was with a male coyote. She was in "heat". She was diffently a cross. And her skull brought a pretty good price. :wink: While the coyote and dog have different scientific names, the genes are close enough for cross-breeding.