You can try to avoid all the situations you try to. If a dog is quick enough, even the most responsible dog owner will have to deal with this. My German Shepherd caught a baby possum. My Lab brought a mouse into our home. A dog (Ridgeback/Pit mix) I house sat for caught a bird in mid-air one time and attacked a skunk. This isn’t a matter of being a “responsible” owner. If a dog is in a backyard and unleashed, or hell, if a squirrel is too close for comfort, that dog is on it. I can understand why this owner said something about the Greyhound. Pretty much all dogs who consider small animals prey will constantly have to be watched.