Now here is some real life experience, thanks for chiming in bacpacker. Am curious to know more info about this situation. Will be interesting to see how the rotation helps, I hope you can come back to report here.They absolutely will eat it to dirt. I have a 2048 sq' run and 11 birds. it was dirt in less than three months. I will be building at least 3 times that size later this year and rotate them thru each section to give the grass a chance to recover.
What part of the country do you live in and what type of plants were growing where the birds were pastured?
Was this during the summer months and was there adequate rainfall or drought conditions?
Were the birds full grown large fowl?
Did they only free range for food or were they supplemented with mash or whatever?
Were they given 24/7 access to this pasture?
Sorry for all the questions, I tend to detail out all the possibilities when trying to come to a conclusion.
This could be a great long term discussion if it doesn't turn into a chat thread.