The only reason I suggested keeping the tractor a tractor and adding a run is simply the run space you have is too small, especially as a stationary unit (the movement of a tractor allows a bit more fudging as it opens up opportunity to explore and forage). You have 5 large fowl, and 36 sq ft - the minimum recommended on here is generally 10 sq ft per bird (50 sq ft in your case) and I always suggest going for more than minimum if at all possible, as it helps alleviate a lot of behavioral problems plus makes for easier clean up, a healthier environment, etc.