Thanks, all of you, for taking the time to give your opinions. It really helps.
I live in California. I just checked and apparently the type of deer in at least one area of the county are mule deer. Before the rain, the leg was a whitish/creamy color from a distance. Can deer be that pale? Is it definitely deer and not a goat?
It couldn't be a dog, since I've never seen dogs run loose in this area (most people have Fifi dogs) and my yard is fenced in anyway. There's only a small gap under the fence that the skunk uses to go back and forth, but nothing bigger than that could get under there. The grey foxes are pretty small (and they like the jump over the fence)... would they or a cat/skunk/opossum be strong enough to carry this leg around? I've never seen my neighbors bring home anything they've hunted, so it probably would've had to have been carried some distance.
Thank you.