RE. the SnakaBall. I have had three horses in total and they've all loved the Snakaball. Sennie took about half an hour to work out there was food in it, then after that there was no stopping him. Now I put a handful of nuts in every night for him, and leave him happily pushing it around the stable. So, old_mare, I'd recommend one for your horse as well.
I've never heard that it can stress a horse Anne11. Who told you that, or where did you read it?