Everything everyone is mentioning are ALL factors as to why midwestern deer are bigger. (abundant food, mineral rich soils, lower hunting pressure, better management practices, shorter gun seasons, better genetics) ALL THESE ARE TRUE!! The debate now is which is the most important. But first i think people interpreted the original question differently. Are we talking rack size, body size, both. etc. Are the animals in the different areas we are comparing them to the same ages? IMO if we are comparing a buck (or doe for that matter) that are the same ages from the midwest and anywhere else the mineral rich soil is the key along with ABUNDANT food in bigger body and rack size. That being said better management practices, short gun seasons, lower hunter #s, etc. enable deer in the midwest to grow up and reach maturity. This does not happen in most other areas. So therefore if allowed to grow older obviously the deer are bigger there!! No matter how rich the soil and how much food there is if someone shoots a buck at 1.5 he cant get big!! The question has multiple right answers-it just depends on how you are interpreting the question. Imo genetics is the least of all influences here no matter how you look at it. A genetically superior buck with poor nutrition will not equal a genetically inferior buck with great nutrition. Thats a fact!!