The question of food is not about acres...that is a variable impossible to predict and I disagree with Grant or any one who attempts to "guess" how much is needed.
Every landowner needs to grow enough food to feed deer year around or they will do exactly as is happening here...go to the neighbors! Certainly each of you know that all land is not capable of producing the same yields so one acre of dry sandy soil cannot produce anywhere near as much as one acres of black loam...so "acres" is irrelevant.
Each landowner must (with some trial and error) grow enough to feed deer year around...that can be done on a 1/2 acre or even a 1/4 acre in some places while 20 acres may not be enough with very high deer densities.
The first step is utilizing crops that can stand heavy grazing and provide food for the longest period of time so always start with white clover. Only in severe cases can white clover be decimated (high deer densities, poor soils or poor choice of clovers)
The second step is to add other crops and where high deer densities are involved that rules out soybeans and corn. In most cases a combination of brassicas and the winter rye mix will fill the need.
So...you start with what you have (any landowner) if you have one acre and they decimate it, then double it and continue to increase both yields (thru proper fertilization, crop rotation and use of the right crops for that situation) until you consistently have feed left over...some turnips uneaten and rye not eaten to the dirt.
If you have outstanding cover (safe secure bedding areas) then you will have plenty of deer and they will require plenty of food but plenty of food can be grown in a fairly small area if done right but it can not be done with ONE food source.
The threads in Dbltree's corner explain in detail exactly how to attract and hold whitetails...but the answer is not in any one thread...it lies in ALL of them. Divide your feeding area and plant 10-20% clover and divide the rest into brassicas and the rye combination found in the cereal grain thread...soil test and fertilize heavily...you'll feed a tremendous amount of whitetails on a small amount of land.
Forget about "how many acres"...that is a variable yet to be determined and no man on this earth can tell you the answer to that....