Our dogs always had a chain with a long run when they were out in the yard. They were never left out when we weren't home, never left out overnight or all day, just when they wanted "out." They were in no way ever aggressive, as they were well-trained, well-socialized well-loved pets.

Being tethered when outside has nothing to do with it, though if she's out on the tether and you and the boys are also out, beware of human feet getting tangled in the line! You'll get nimble about it after a bit! And all our dogs, except Gracie, the Great Dane, learned how to untangle themselves. Gracie, sadly, just wasn't that bright, and would sometimes wind herself completely around the lilac bush, for example, then bark to be let in because she was stuck!