How much of a DNA difference is between Chicken of the Woods, and Hen of the Woods?
I will assume from your comment that your question is


  Is a chicken of the woods just a hen of the woods growing on the side of a tree?


, which is very similar to me to 


  Is a chicken of the woods and a hen of the woods the same species?


No, they are not the same species. Chicken of the woods is the common name of a number of species of the genus Laetiporus. Hen of the woods is the common name of the species Grifola frondosa. In fact, Grifola and Laetiporus don't even belong to the same family but only to the same order (order Polyporales).

According to the wikipedia links posted above, Grifola frondosa is indeed usually found at the base of the tree while Laetiporus is generally found in the wound of trees (mainly oak trees).