People feed deer corn for multiple reasons including hunting, trail cam observations, and just watching deer in their back yard. feeding deer seems harmless since deer eat a lot of corn, but it may be harming the deer.
Foundering is long hooves on a deer that causes a lot of pain. Foundering is almost always the result of a deer consuming too many carbohydrates in the diet too fast. i.e. corn
The result is a buildup of acid in the rumen, which kills the bacteria that digest carbohydrates. This action then results in an increasing pH in the blood that can hurt or possibly even kill the deer from acidosis.
White-tailed deer that have foundering long hooves will often walk on the backs of their hooves because the acid buildup agitates the growth plate in their hooves. As a result of the deer attempting to ease the pain, the hooves grow more extended than usual because the hooves do not have proper contact with the ground. Without adequate contact with the ground, the hooves do not wear down as they usually would.
Since deer do not only eat corn, feeding them in the spring summer and fall usually are not a problem. The problem is generally caused in the winter when deer will consume a large pile of corn because that is all they have. Foundering hooves are not common, but if you are feeding deer, it is something to watch.