Probably worth more for straw than feed.  If you have the option, mow it with a flail chopper or something that will break it up.  Long rye is hard on a baler and even harder on a manure spreader.  I used to know a hay and straw broker who sold mostly to horse stables, and yes, he eventually went bankrupt.  One of the most in demand products he handled was rye mowed just as it headed out and baled for straw.