i have my boy go after coyotes a few times too, by my spot though its totally empty so now chance of them running out across a street or something, they are way too fast for him to catch. i bet your dog has a good chance at catching one though as im sure shes fast. usually they are pretty small thin animals, although one time i did across a very large strong one, probably about 60 lbs or so im guessing. we actually came across a pup twice, luckily my dog didnt hurt it, and i leashed them up and left it alone soon as we had left about 10 yards mom came and they took off.