If your barn ceiling has water damage from collecting condensation, you might need to consider taking a step like this. We've consulted on the building of very large barns equipped only with natural ventilation, and it works very well. Duct systems are most applicable for very large barns, where air might not circulate efficiently from one end to the other without help. Finally, take a moment to think about insulation. Because an insulated barn maintains a slightly greater temperature difference between the inside and outside of the structure, air movement tends to be slightly intensified.
Insulation also reduces the risk of condensation buildup.
It's not always easy to install insulation in an existing structure, but it's an option worthy of exploration. According to the Equine Research Centre's studies, it's hay. Susan Raymond, research associate with the Respiratory Health and Air Quality project at the ERC, explains that in one study, dry hay demonstrated dust levels dozens of times higher than hay cubes or pellets. Bedding is another major source of inhalant particles in the equine environment. The worst offender, according to the ERC studies, is straw.