Well just like a dog they are just now blowing coat and getting there winter attire....notice a differance in the color of the adult deer? because some not all have gone from rust to brownish grey....it's the weather
I do not agree that it is driven by weather. For one thing, the midwest has had an unusually cool Aug. and Sept. Secondly, if this were ture than deer in warm climates (Fla.) would never change coats.
IMO, deer react to one factor more than any other, photocycle.The length of the day is the only factor that is consistant in the deer's world over the long haul. Deer that are born late do not have the physical ability to react to the photocycle in a healthy way.
But honsetly, I'm just spouting off semi-informend opinions. Take all of us with a grain of salt. [:)]