Planning the perfect chicken coop part

Mark and I are still in the
planning and negotiating phase of designing a new chicken coop. 
My long-suffering husband agrees with all of my features
of a perfect chicken coop, but what’s most important
to him at the moment is aesthetics.  He wants to order a Starplate
building system for a bit over $100 and turn it into a coop like
the one shown here.



Even though I was the
art major, I also don’t seem to have a problem with plain old
rectangles — probably because I’m also a cheapskate and know how much
less rectangles cost to build with.  However, I figure it’s worth
letting Mark have his way if he gives me an external nest box and a
wide door. 
Plus, it’s quite possible the pentagonal shape will be easier to shovel
bedding out of than a rectangle.



The big question mark
right now is the roof.  Due to crazy winter weather keeping our flock cooped up, I’m tempted to make a
clear roof that can be made opaque for shade in the summer. 
Options for the clear layer include cheap greenhouse plastic (but that
would have to be replaced perhaps every year or two) and clear roofing
panels (but they might not be structurally sound if cut into
triangles).  I’m pondering simply cutting triangles of styrofoam
insulation to fit up under the roof in the summer, providing a bit of
heat reflection as well as shade.  Other ideas are appreciated!