i just read an article in the magazine The Natural Horse about recycling objects for your horse....and she mentioned her horses love to play with empty milk jugs. might be worth a try!

Most horses won't do much with horse toys in a stall. A few will play with a tether ball.

I've seen two horses in pasture playing tug-of-war with a discarded hay net. They'd pull against each other for a bit, tossing their heads around, until one got the net. The winner would then hold up the net so the loser could grab hold again and they could go on playing. That was fun to watch. It's not a good idea for a paddock situation, though.

Take this with a grain of salt OK? This is what I did for my boy when he was about 4 yrs old. Got cardboard boxes - no staples, tape, stuff that would cut an amimal on it or embedded in it. The boxes ranged from big to small about 3 of them. Then I put some horse cookies in the small one....closed the top, put it inside the medium one, added more treats, and put it inside the big one, closed the flaps on the tops of all 3 boxes. Dropped it off, went to work, and heard the story when I got back to the stable that evening. He had a blast of a time pawing it, rearing on it, throwing it with his teeth, ripping it apart................... card board was every where, no one was injured, he looked forward to boxes after that. Just an idea................perhaps you'll get a creative idea that would suit your horse's gum and suspensory limitations? Best wishes! Oh one more I read about was a woman who got old used brushes from street sweepers and set them up in her yard. The horses loved rubbing against them.