Do you have to worry about loose dogs (pets) where you hunt fox? The hard thing is not shooting foxes when you're yote hunting (I live in Ohio, but hunt Texas yearly). So you prob aren't worried about mistakenly shooting a coyote. Have to know the features and way they move to help ID outside of say 100yds (inside 100 is easy I'd say). I'd go 200yds or more if you are versed in how the move. Of course a lot further under the right circumstances.
In this video I had 2 yotes come barreling in from 500+ yds out, no question even at that distance they were yotes and I was using a lower res spotter. They were about 150 yds out when they stop on top of the hill.. https://www.youtube.com/watch?v=e99FtNW-C3s