It wasn't too hard to remove the rails.  I am not very handy so I used small crowbar and gently pulled away the frame.  Kept the pieces for scraps. 
Here are a few pictures - one from a few years ago and one more recent.  I attached some shower curtains to keep out the wind, rain, and snow.  This worked well and they liked to hang out under in there when the weather was bad.  I also added a small fan, vent holes, and motion lights.  It inside an 'enclosed' run as I have too many predators.  Some day, when I have enough money, I'd like to build a proper enclosed run.  
During the colder months, I moved the heated Premier 1 waterer under the coop so the plastic would block the wind.  I found that if got below freezing and too windy, the base and nipples would freeze when unprotected. 
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