I know that the average recommendation for sq ft per bird in a permanent run is 10sqft per bird, but how much is recommended in a tractor that they will only be spending the day time hours in and then go back to their permanent coop/run for the night? Also, has anyone ever put a wire apron on their chicken tractor to help deter daytime diggers such as neighborhood dogs? We're thinking it would be easy to permanently attach a 2' wire apron all around the base board of the tractor and then permanently attach another board, say a 2x4, to the outer edge of the apron. Then when you want to move the tractor, just pick up the 2x4 boards which will pull up the wire apron and use double ended snaps to snap the apron wire to the side of the tractor wire which would hold the apron up while you move the tractor. Then unsnap them and lay the apron back down. Anybody tried this and if yes, did it work well? Thanks!