IMO this system is just a complicated way of attempting to replicate tractoring. The grass will eventually get burnt out, the nitrogen will eventually start to pile up, and if the padocks are too big the chickens will probably only hang out in one area, killing off all the grass in that corner leaving the rest untouched. If its too small then they will wipe out all the grass period, and i'm not entirely sure that you can find a "just right" in this case. I have seen some very cool techniques where the coop is in the middle of a large garden, one side is the chicken run and the other is the garden, and these switch off yearly, preventing the ground from getting too burnt out from either the crops or the birds. I came off negative, but i really don't want to discourage you, its a great idea, i just think it needs a little tweaking, so please do keep us updated.