Most of my chickens are free run and there is enough of everything for them sample - but not destroy. Occasionally I have to keep some in a run that now has very little left growing in it. I'd like to plant some plants that do well with the excess nitrogen and are not so tasty to the chickens that they will denude them. I will place some old bedsprings over the transplants to discourage the chickens from digging it all up before the new plants get established. What plants will they NOt eat? I am starting with Horseradish and Tansy.... any more suggestions out there?