How about grain sorgham for the summer (not really to feed the deer, but for the root system and to build biomass and topsoil for your fall killing plots)
Grain sorgham will produce a lot of bio mass but consider a blend to produce biomass, food, root systems and nitrogen and replace the sorgham with sun hemp.
Try this;
Sun Hemp at 7 lbs/acre
sun flower at 4 lbs/acre
Clay pea at 8 lbs/acre
buckwheat at 8 lbs/acre
Forage bean
tall type at 22 lbs/acre
Balansia clover at 2 lbs/acre
spring oats at 10 lbs/acre
Thats 7 species at 60 lbs/acre that will provide food all summer plus lots of cover, biomass, nitrogen and root systems to help with erosion control and loosening the soil. This is the soil building summer blend I use in rotation when not planting eagle seed gamekeeper soybean blend.
Follow this with a fall planting of cereal rye, turnips and diakon radishes plus another 2 lb/acre balansia clover at the end of august. The balansia is an annual clover that will readily reseed if allowed. very tolerant of cool weather but does not like hot weather. After the fall planting expect an explosion of clover that vines the following spring, knee deep and difficult to walk thru, just remember it will not survive the july heat. If you wish to follow the winter cover with a spring planted summer crop you will have to terminate the clover as it will out compete most anything.
If you wish to add sorhgum to this add no more than 2 lbs/acre as it will dominate and shade out other species.