Hmmm...My inlaws have a trailer on the Eastern Shore of Virginia that has weathered dozens of hurricanes since they bought it used in 1961. There is also a shed that has been there as long as I have known them, since 1987 at least. The secret to keeping any lightweight structure like a shed or trailer from blowing over is the tie down anchors.
If you have a coop that resembles a tool shed and just sits on it's foundation you need to secure it. I would use steel cable with turnbuckles, or Simpson Strong tie galvanized strapping. You will need to secure the straps over the shed in an X, so it is protected from multiple directions.
The hard part is anchoring to the ground. There is something called a sand auger, a spiral of steel with a welded eye. You run a stout rod through the eye and screw the thing WAY down into the sand. If you used cable to go up and over the shed, you can use the turnbuckles to take up the slack. On my house I have the Simpson hurricane banding bolted to the foundation, so I am uncertain how to attach it to an auger eye.