I was concerned about feeding them hay, as I have heard so many stories about impacted crops, and most of them seem to involve hay or straw or grass. But many here have given them hay, and they really enjoy it, many others have free-range chickens that have access to hay. So I do give my girls a flake of alfalfa every other day or so. It really gives them nice orange yolks, and keeps them occupied. I make sure they always have other food available, and plenty of grit, and I have never had problems (@ 6 months?). So it is pretty much up to you whether or not you feel it is safe.