My friends horse consumed a thick produce rubber band

Hello, I was visiting my friend who has 2 great horses. When I visit I like to bring them a little treat other than the grass or hay they graze on. Last time I brought some apples today I brought some carrots. What happened was without me or my friend knowing, a produce rubber band fell out of the bag, I didn't see nor my friend when we looked over one of the horses picked up the rubber band and started chewing on it, my friend tried to open his mouth to get it out but the horse had swallowed the rubber band. I am concerned it could get caught in his digestive track and harm him. Can you let me know what could happen and what I can do? I will forward your responses to my friend who I am sure may be concerned about his pet as well. Thanks so much for your response
Cloudburst99

It *should* pass without issue - however, it is important to keep a close eye on the horse in case a complication does develop. IF you notice any change in the horse, seek medical assistance.

Thank you themacpack---I'll let my friend know-----question: how long would it take before the rubber band passes out of the horse? My friend might be able to locate it in its feces----the horse ate the band about 3PM eastern time 7/30
Best wishes,
Cloudburst99