My future coop is a converted metal shed (like a pole building). The only opening besides the entrance door is a small (2' wide by 5' high) screened door that leads to the run. In nice weather & even not-so-nice I can leave this door open for air inside the coop as it is covered by an overhang. The doors are not airtight so there is some air movement inside when they are shut. I'd like to add a window for ventilation. How hard would it be to cut into the siding to add a small doublehung window? I am a total doof when it comes to construction and would have this done by the neighbor who is redoing my fencing for the yard.