Watch the dog some will catch up with a rabbit and go for the strike straight away others will faingt one way, then when the rabbit turns the dog is there to catch it. It is nothing you can teach the dog has to learn it for it's self, the same as standing off hedges, I had a whippet once that would always get between the rabbit and the hedge, not many escaped.
TC
yea he very rarely runs straight behind, runs very boxy but not too much if you know what I mean