I've been feeding these for over a week now and not had any problems... touch wood. There's another bf tb on the yard who's been on them 6 months without a problem. Try it and see.
Not graze on as such but I bought small bales of oat straw for lami girl and there's LOADs of dried grass in it, just like the bagged stuff! Was worried but have been feeding it for 3 weeks and she seems fine on it (apart from the extra calories which kind of undermines the point of the oat straw!). I wouldn't feed loads and loads tho..
I've been feeding their grass nuts and gold blend chop for about a year now with my barefoot pony with absolutely no problems at all. I really rate their products