There is no exact science as to when the rut starts but as a general rule its around the last 2 weeks of September. However, factors such as weather and temperature play a role in 'getting them going' as well as location. There will be differences all over the country as to when the Fallow in that area start to rut, even locally. Mine started a week before a friend of mines did and he is only 13 miles away from my ground. You can hunt Muntjac all year round and the bucks will still be in hard antler, same goes for Red and Sika stags. The does and hinds dont come into season until the 1st Novemeber and Roe bucks wont be in either. The best time to come for Roe is early August in the rut, however, no other deer will be in season except for Muntjac, but the bucks will have cast their antlers. So you would do Fallow bucks, Red and Sika stags at the same time but you would need a return trip for the Roe.