This is very similar to grazing cattle in different enclosed pastures. Ranchers have been using rotation for many years. Applying it to chickens makes sense. The portable run seems just as labor intensive as the tractors; however, I like the idea of segmented runs. It would be difficult for me to do this though because it requires a lot of space. We live in 1/3 acre in a suburban community and our hens are kept in a U-shaped run behind and along the sides of our greenhouse. While the run over 40' in total length and 5ft wide, I think it would be difficult and cost intensive to divide the run in segments and control the chickens access to each segment. Also, enough segments are needed to allow time for the "pasture" to recover after grazing. I'd say at least 5 segments are needed - 1 active grazing area and 4 recovering pastures with a weekly rotation of the chickens. This is because I know my 5 hens (soon to be 7) are able to devour all plant matter in their run in about 1 week and it takes about 4 weeks for plants to reestablish themselves. For my case, that would mean five 5'x8' runs. I feel like 5 hens (let alone additional the two chicks we are growing out right now) need more space than 5'x8' even if they do get fresh ground every week.