Which piece of equipment is most suitable for preventing horses from chewing tails?

The most suitable piece of equipment for preventing horses from chewing tails is hot chili pepper powder. This option acts as a deterrent because the taste and sensation of the chili powder are unpleasant for the horse. When applied to the tail, it discourages the horse from chewing by making the behavior uncomfortable or unappetizing. This method is commonly used as a repellent in various contexts, as it is a non-invasive solution that allows the horse to remain comfortable and mobile while minimizing tail-chewing tendencies.

The other options do not effectively address tail-chewing behavior. Mirrors, for example, may engage a horse's curiosity but do not actually prevent the behavior. Leg chains and hobbling are restrictions that can lead to discomfort or stress in the horse, which does not address the underlying issue of tail chewing and could exacerbate behavioral problems instead. Therefore, using hot chili pepper powder is a targeted approach that discourages the unwanted behavior effectively without causing harm or distress to the horse.