Training Science Articles:
My friend Mary Richards (a previous zoo keeper at Disney's Animal Kingdom) has put together a wonderful list of enrichment options commonly used in a zoo/exotic situations. These have all been vet-approved by a zoological vet, so in general terms they are safe. Though we do advise supervision with all new toys. Remember we want our enrichment to be species appropriate, we want them to become a healthy outlet for natural behaviors that may not be possible in domestic situations. We want our enrichment to build their confidence and curiosity, so we need to be sure not to over-face our individual horse with a toy that is too much for them (yet).
Here we go-
Scents: Perfume Essential oils Extracts Fresh herbs/dried spices
These can be placed anywhere, really.
Ice pops/cubes: Water only, with produce/treats, with dilute juice, with electrolytes, with extracts
Auditory: Recorded animal vocalizations, Recorded nature sounds, Music (there is a paper put there that says horses prefer country and classical to rock or pop), wind chimes, singing
Flashlight/laser play- obviously, please do not shine in eyes
An important thing to remember about enrichment is that novelty is key. A ball left in a stall for weeks on end is basically just white noise.