How come this year a lot of deer look really mangy? their fur is almost all gone and some skinny. what causes them to loose their fur like that? lack of food,water? i know my buddy and i have a few pics with deer looking like this along with Millertime's pics.

A lot of things can make a deer look this way. Has it been very dry where you are seeing this? Drought type conditions cause the food supply to void of the proper nutrition as well as limiting water. It could also be some type of desease or heat related if you have extremely hot temeratures that are not normal for your area. I've seen this before with the whole deer herd and at times just a few animals within the herd. During the heat of the summer a lot of the South Texas deer look pretty mangy mainly due to the heat.

agree hot and dry

I would tend to agree with that though I would also suggest that deer tend to look that way at times when their coat is changing from summer to winter. You also said it yourself though....mange in some cases.

during parts of the year in central IL it has been dry as a bone. but have only seen some deer around in IL like this. hard telling, but it is probably is just their coat changing or nutrient/water lack.