Sparrows do it. Donkeys do it. Elephants do it. And ostriches do it. It makes sense to me that a big feathered dinosaur like Yutyrannus would take a dust bath, too.
I checked with a couple of paleontologists and they said that the 30 foot long tyrannosaur relative would more likely squat down with their belly to the dirt than roll over on their side.
In this short video of the process, I take you behind the scenes. (Link to Facebook video)
My sketches are in gouache, which gives a quick impression that I can show to the art director of Ranger Rick Magazine, where the illustrations appear in the March 2017 issue.
I make a new maquette because none of my existing dinosaur maquettes are in this pose. The head looks big because of camera distortion.
The sculpt is made with a 2-part epoxy called Magic Sculpt over a core of Sculpey. I use aluminum wire for the armature. (Thanks, Clayton) Even though the maquette doesn't have a feathery surface, the big planes are clear, so I can light it and have a sense of light and shadow.