Why do we feed free choice hay at HHS? First off, horses are grazers by nature. This means that they are used to eating small amounts of food all day long.
Providing a natural grazing environment (ideal or not) allows them to manage their own weight control. They do not feel the need to over eat during meal times and then stand around doing nothing for hours on end. Providing free choice feed, whether on pasture or selected feed such as round bales, gives all the horses the option to eat whenever they feel hungry. Unlike us humans, their digestive system is not set for 3 square meals a day but rather for a little here, a little there.
Also, when we take our horses out on the trails for example, we stop and let them do a little grazing at select times to encourage the healthy digestive enzymes to keep working rather than to build up into acid indigestion which can result in more serious conditions such as colic or tying up. Also unlike many stalled horses, they generally stay away from chewing the fences out of boredom.
We have been free feeding our horses for 8+years. With the exception of the odd horse under or over weight, 99% of our horses are well within the healthy range of weight. This is primarily due to the fact that they can all eat when and where they want.
Of course in herd dynamics there are always one or two that are the more dominant and "occupy" the food, but when free feed is available there is always more than enough for everyone. We rarely have to stall horses to ensure that they get enough food and nutrition.