Are there any toys I can make for my horse to break stall boredom?

In reality he isn't actually in a stall, my horses are in a pasture 24/7 but they have a run in shed that is connected to the tack room, we have boards on the walls for support and protection, but my 6 yr old has started to crib, I've always heard that if a horse is in the pasture you shouldn't have any trouble with Stable Vices, well I guess they're wrong. Anyway my question is this, are there any cheap and easy toys that I could make to hang from the rafters for him to play with while they are in there, to distract him from cribbing? or something I could buy for them. I really don't know what to do and from what I've heard Lik-Its don't work all that well, and some horses don't like them, I'd rather not spend $40 dollars on something my horse isn't going to like. Any suggestions?