I guess that you don't have muntjac where you are. Two of my friends have had whippets killed by muntjac bucks in the last couple of years and another mate who is a keeper is under standing orders to kill every muntjac seen on the estate because of the damage done to the landowners whippets by them.
No mate , I confess I,v never even seen a muntjac ,but back in the day I did have some experience of roe and fallow , I,d also say that although I have worked my dogs steadily over the years , I don,t work them as hard or on the amount of game that a lot of people on here seem to do , so