We currently are running 34 SQ/ft per bird in a 4 "pasture" set up for our standards. The biggest factor is the weather. When you are getting good growing conditions and plenty of moisture, the birds won't keep up with the growth. Occasional string trimming may be needed.
When we get into late fall and the dry period all the runs will show some stress and overgrazing. We combated this with some luck....coop was built with a well and gravity pump nearby. We used hose and some cheap sprinkler heads to keep things growing. Without irrigation on the pastures we would be going into winter with 4 beat up runs.
During the winter we keep them in one run (partially covered) and basically sacrifice it. Late Winter, early spring is a good time to frost seed pasture mix on the other three areas. Once growth reaches 6 inches we start them through rotation in the spring. We started off with a 10 day rotation and that was good as long as growing conditions were decent. 10 days gives 30 days of rest to each pasture which is ample for any interseeding to take hold and poop to break down to acceptable levels.
I would make the areas as large as possible and be sure to have access to all areas for a wheel barrow, tiller, etc.
Good system, very happy with it...got the idea from Joe S's information.
