captive five foot mussie i see are thin but the wild caught are massive with a thick girth like a indigo snake I wonder if it is from proper diet. King snakes fed rats start to whither also.

Naturallly in the wild the mussie is a girthy snake.

Here is an average size one https://gallery.kingsnake.com/data/76098big_mussurana.JPG but a big one is very girthy from the pictures I see of herps going to SA and catching them.

Every captive one i see is like a rat snake.