My chickens free range in my back yard. The grass part of the yard is flat, and as you go away from the house, there is a hill that goes up at about a 45° angle and then there is a forest behind that. The hill is covered with mulch to prevent erosion. Well, the chickens are digging up the mulch hill so much that there are areas that are just sand now, and everything is washing down into my grass yard. I don't know whether to order more mulch, or should I try to plant something on the hill in the spring? I have already lost about 2' of my grass yard all the way around where the mulch has been scratched down the hill. Here is a photo - please advise!