Purple top turnip

I let my nephew make a food lot for the deer each year.  He uses a annual type turnip so there isn't any danger of turnips taking over.  In the winter the starch in the green tops turns into sugar.  When Indy and I went through before the last snowstorm, the deer have gone through the area chomping off the tops.  There were also whole turnips lying on top of the ground.  Some had been chomped and others, like this one, were whole.  Why turnips were out of the ground and uneaten, I don't know.  I looked up this type of turnip and it's edible.  Suppose it's too bad I'm not into turnips.